Grading out offensive lines is a difficult task. Other than sacks allowed, there are no commonly used metrics that can distinguish a good offensive line from a bad offensive line. We can try and judge by the naked eye and make claims like "Man, he gets beat a lot" (Robert Gallery at tackle) or "Wow he sucks, he has so many penalties" (Good afternoon Kenyatta Walker). We can try and listen to the talking heads about how one guy uses his hands as weapons, while the other doesn't swivel his hips enough.
But that doesn't really let us evaluate the offensive line. An offensive lineman's performance can be affected by the scheme run, the opponent played, and even if the team is protecting a lead or trying to mount a comeback. Other issues are the quality of players around you, specifically the running back. The best offensive lines can be made to look dismal with a below average running back while a bad line can be made to look good with a great back.
But how have they performed as a group? There are a few more advanced metrics that attempt to value the offensive line based on several different factors. I'll introduce those metrics, define them both in the technical terms as well as an easier to understand version, and then we'll look at how the Bucs fared in those categories.
Hit the jump for a look inside the numbers.
I was motivated to do this look at offensive lines based on Tomahawk Nation's excellent look at the FSU OL. The available statistics between the college game and professional game vary, but there are still some telling statistics to be looked at.
Let me be the first to say that I was/am very high on the Bucs offensive line. As a unit they have all the makings of a strong, aggressive unit. Davin Joseph, Jeremy Trueblood, Jeff Faine, Arron Sears, Jeremy Zuttah and Donald Penn all fit into the mold of what you want in an offensive lineman. We've heard for a year or two how some of these guys are future Pro Bowlers, and I have no doubt that as individuals, some of these players will take home some awards.
Let's take a look at 2008 numbers on the offensive line, which are provided FootballOutsiders.
To get you comfortable with some of the statistics/metrics that will be used, let's look at the explanations on FootballOutsiders (or FO).
Adjusted Line Yards:
Teams are ranked according to Adjusted Line Yards. Based on regression analysis, the Adjusted Line Yards formula takes all running back carries and assigns responsibility to the offensive line based on the following percentages:
Losses: 120% value
0-4 Yards: 100% value
5-10 Yards: 50% value
11+ Yards: 0% value
These numbers are then adjusted based on down, distance, situation, opponent, and the difference in rushing average between shotgun compared to standard formations. Finally, we normalize the numbers so that the league average for Adjusted Line Yards per carry is the same as the league average for RB yards per carry, (which is 4.08 yards)
In language that us regular folks might understand, each running play has a specific value for the offensive line. If a running back gains 4 yards, the OL is credited with 100% of that, or 4 yards. If the back is hit for a loss of 2 yards, the OL gets credit for -2.4 yards.
It also mentions it "adjust" the numbers based on down, distance etc. What this refers to is 5 yard gains are not created equally. A 5 yard gain on 3rd and 15 is not as valuable as a 5 yard gain on 3rd and 4. Additionally a 5 yard run from the opponent's 5 yard line is worth more than a 5 yard run from midfield.
Using Adjusted Line yards (or ALY), let's see how the Bucs fared in 2008.
|Rank||Team||Adj Line Yards||RB Yards|
I can already hear you asking, "so what does this mean?" Remember that in Adjusted Line Yards, 4.08 was the league average. The Bucs OL was very slightly below average in this category, coming in at an ALY of 4.04 yards per carry. Additionally, the running backs averaged 4.09 yards per carry (this is in the standard metric we are used to seeing). To put it all together, on a given carry, we can expect a run of 4.09 yards, with 4.04 yards of credit going to the OL and .05 yards going to the running back. Our running backs are basically going only as far as our line will take them and were below average in 2008.
Another way of looking at this is our running backs are extremely dependent on the offensive line on any given running play. For comparison's sake, the Giants were at the top with an ALY of 4.62 and a YPC of 5.28, while the Bengals were at the bottom with an ALY of 3.31 and a YPC of 3.22 (their running backs actually gained less than what the OL provided)
This is somewhat of a shocking number for all the accolades our line received from staff, media, and fans alike. They were average, ranked 22nd in the NFL in adjusted line yards in 2008. Had you asked me before viewing these numbers, I would've guessed top 12. The ALY does vary based on where the run goes (off tackle and to which side), but we'll cover that later. On to the next metric
Percentage of runs on third or fourth down, two yards or less to go, that achieved a first down or touchdown. Also includes runs on first-and-goal or second-and-goal from the two-yard line or closer. This is the only statistic on this page that includes quarterbacks.
You might call this the "smash mouth football" look as it looks as running plays on short to gain situations. Goal line runs, 3rd and 1, 4th and 1 etc. With big nasties like Trueblood and Joseph, we had to fare pretty well in this category, right? Let's look at the 2008 numbers and see.
|Rank||Team||Power Success||League Avg|
Again, mildly disappointing. Just below league averaged and in the bottom half of the league. We converted 65% of our "power success" opportunities, good for 17th in the league (bottom half) and slightly below league average. The tops and bottoms of the league were Carolina at 79% (I think we contributed to that number) and San Francisco at 52%.
With an undersized "power back" in Earnest Graham, and injuries at fullback, this might help explain some of the lack of success. This has to change this year if we are going to a run-based offense. We'll have more than our fair share of 3rd and short and I would put a 70-72% range as a reasonable benchmark to be successful.
Now that we've looked at the short yardage situations, let's look at long or breakaway runs.
Percentage of a team's rushing yards more than 10 yards past the line of scrimmage. Represents yardage not reflected in Adjusted Line Yards stat.
This seems easy enough. Look at all the yards that are more than 10 yards past the line of scrimmage. Then take them as a percentage of the total yards.
The thinking here is, once a running back gets 10 yards past the line of scrimmage, the offensive line has done their part. This yardage is fully dependent on a running back making people miss or breaking tackles. This is a measure of the breakaway ability or big gain potential of a team. Any yards gained on a running play after the initial 10 yards is not counted towards the offensive line for those reasons. How did the Bucs fare?
|Rank||Team||10+ Yards||League Avg|
Alright, our first ranking in the top 50% of the league! It comes in a category that I wouldn't have expected. While Earnest Graham is a good back, I certainly don't classify him as a breakaway threat. But with him being the primary ball carrier, we achieved a ranking in the top half of the league. While still a bit below league average, we can see that 18% of the Bucs yardage in the running game came from beyond 10 yards outside the line of scrimmage. To put it in context, the top team in 10+ Yards was Carolina with 27% and the lowest was Indianapolis with 9%. Those seem about right.
I'd expect that number to be a bit higher next year. With a dedication to the running game that we didn't see under Gruden, it should wear down defenses and allow for bigger gains. Most of Graham's long runs last year came in the 4th quarter and with Derrick Ward and Cadillac pitching in, the defense should be dead tired come the end of the game.
Let's get to the first metric where a lower number is better.
Percentage of runs where the running back is tackled at or behind the line of scrimmage.
Carries for a loss are never a good thing. A running back falling forward, or getting back the LOS can sometimes be a great play, taking a 3 yard loss and turning it into a short gain. The "Stuffed" percentage is one you want to be low, or be at zero.
Another good ranking for the Bucs. Opinion time. This would seem to be based on both the line's ability to at least get a hat on their guy, but also the decisiveness of Graham. As a one cut runner, he doesn't do a lot of dancing in the backfield, which (in theory) would diminish his chances for being hit in the backfield. The Bucs OL ranked in the top half of the league and even came in a bit better than league average. It's an interesting contract to the Power Success numbers. So while we aren't getting hit for a loss that often (in comparison to league average), we aren't converting the league average of short yardage situations.
Sack Rate represents sacks divided by pass plays, which include passes, sacks, and aborted snaps. It is a better measure of pass blocking than total sacks because it takes into account how often an offense passes the ball. Adjusted Sack Rate adds adjustments for opponent quality, as well as down and distance (sacks are more common on third down, especially third-and-long). Sacks are just what you think, total number of sacks given up.
I'll do my best to translate here. The Sack Rank percentage will give us the adjusted percentage as to how often a sack occurs. To help better define this, let's look at an example. We'll look at Team A who passes more than normal (think Colts) and Team B who runs more than normal (think Ravens). Both teams give up 40 sacks. Sounds like it's pretty equal, right? Well, what if we add in that Team A had 600 drop backs (got sacked 6.6%) and the Team B only had 400 drop backs (sacked at a rate of 10%). I'd say that leads to a compelling conclusion that although the same number of sacks were given up, Team A's OL performed much better. That's just one of the factors that plays in, but you can see that number of sacks is not a truly defining measure.
|Rank||Team||Sacks||Adj Sack Rank||NFL Sack Avg||NFL Adj Sack Avg|
A pretty disappointing number. Ranked 22nd in the league, the Bucs gave up 36 sacks compared to a league average of 32. "But I thought you said total sacks isn't a good measure of an OL?". You're right. Our Adjusted Sack Rate was 7%, meaning on 7% of drop backs we can expect a sack (based on a 30 drop back game, that equates to 2.1 sacks a game). The league average was 6.2%, so again, we were worse than average.
The highs and lows were as follows. High and Low total sacks given up goes to Giants/Pats with 12 and the Lions with 55. As far as Adjusted Sack Rate, the Broncos were tops at 2.8% with the Bengals last at 9.7%. Based on a 30 drop back day, that's a difference of 2 sacks a game. Pretty remarkable.
Alright, so we've looked at a variety of new stats that measure the offensive line. I'd say the numbers were a bit startling. How can our offensive line that is so young and so good (according to media) perform this poorly? Well, there are a couple of potential causes. Offensive scheme, play calling, injuries. Gruden was never much a running game guy and often abandoned it early. In 2008 we didn't have a great blocking fullback, our running back (Graham) while good is still not one of the elite runners, he was injured giving way to Warrick Dunn who definitely slowed down as the year went on and we weren't able to convert short yardage situations.
While this may lead you to want to jump off a bridge, you may want to hold up. The zone blocking scheme can be a great catalyst for our offensive line. The backs we have fit that system (one cut and go), we do have talented players on the offensive line, and we have now added another 1.5 backs to the stable (Ward and a Caddy/Clifton split). All things being equal, we should improve upon these numbers if Jagz and company stick to the gameplan.
Speaking of game plans, how did the Buc's offensive line do when running the ball in certain directions? This will all be based on ALY (explained up towards the top). We'll look at how they did running left or right, and end versus off tackle versus up the middle. We'll also take look into how often we ran in what direction.
We'll look at each split individually in terms of ALY and how often we ran that direction. First up, runs off left end.
|Team||ALY||Rank||% of Runs|
Ugh. Running off left end was not kind to the Bucs offensive line. This would be in Donald Penn's direction and you can see, we not only ranked 30th in the league, we are a full 2 yards below average. The good news? We only ran off left end 7% of the time, far below league average. Maybe a sample size issue, but nonetheless, our runs off left end didn't end well.
Let's take a look at off tackle runs to the left side.
|Team||ALY||Rank||% of Runs|
Again, well below average. Apparently running to the left wasn't a strong suit in 2008. We're about half a yard below average, though again, we ran to the left significantly less than the league average. It's tough to blame individuals based on these metrics as you don't know the outcome, but its safe to say Penn's side of the ball didn't hold up in the running game. I wonder if we ran less that way due to poor performance, or had poor performance due to running that way less. The chicken or the egg argument I suppose. Let's leave the left side and get to the runs off guard and to the middle. For clarification purposes, and per FootballOutsiders
research so far shows no statistically significant difference between how well a team performs on runs listed middle, left guard, and right guard
This just means that off guard runs are counted as runs up the middle for statistical purposes. Here are the numbers for "up the middle" runs.
|Team||ALY||Rank||% of Runs|
Now we're talking. These runs would have been over Arron Sears, Jeff Faine, Jeremy Zuttah and Davin Joseph. The Adjusted Line Yards here show the line providing 4.35 yards per carry. Above league average, but it looks like this is where the majority of the runs took place. Can't say I see an issue with that. We hammered the ball up the middle and succeeded. The perception of those 3-4 players is that they are the strongest (or most skilled/complete players) on the offensive line, and their ALY does nothing to deter from that statement.
Well, we've seen success up the middle and we've seen some horrific numbers on the left side, how did the right side fare? Let's venture into Jeremy Trueblood's territory.
|Team||ALY||Rank||% of Runs|
Back to being below average. It was a nice run while it lasted (bad pun intended). Going off right tackle, the line is averaging 3.91 yards per carry, about .2 yards below league average. At the bottom of the pack, again. We were close to league average in terms of number of runs off right tackle, but again, not quite evenly distributed with the league average. Any predictions on the right end runs?
Let's see if the pattern continues with runs to either direction not performing.
|Team||ALY||Rank||% of Runs|
We hit the league average square on the nose, but still are in the bottom half. And again, we ran outside less than average. While not quite as bad as the left side, the runs to the right side were still below average and under that magical average of 4.08 ALY or YPC.
With virtually the same offensive line coming back and same backfield with more depth, this should be a good tool for the new offensive coordinator, Jeff Jagodzinski to look at. We will be going with a different blocking scheme (zone vs man), but the data seems to indicate that the strength of the line in the running game is up the middle.
So what did we learn? We definitely picked up some non-common metrics that can help us evaluate an offensive line's performance. On a team-centric basis, we see that in the passing game, we're giving up a sack about 7% of the time based on our offense (again, 2008 numbers). We saw that while the gross number of sacks was about in line with the NFL average, we were still giving up about 2.1 sacks a game based on offense, opponent, and other factors.
The running game, specifically the OL were a bit of a disappointment. The ALY was a touch below average, as was the power success rate, a number I fully expected to be in our favor. The Stuffed numbers showed that the Bucs OL and running game were better than average at getting hit in the backfield (in a good way) and the running backs, while capable of ripping off 10+ yard runs, still showed to be more of a ground and pound type system.
With a new scheme, new OC, new coach, a great addition in the backfield, and a healthy (crosses fingers) backfield and line, I expect us to improve in each category, across the board. The 2009 season is here, we'll keep an eye on these new metrics to see what changes are made and how they affect the team.