While recently looking over his stats for a post I discovered that Davin Joseph is one of the worst consistently employed guards in the league. While I knew he'd had a down year this year I had previously thought he had been at least a decent guard. This appears not to be the case at all, at least according to Pro Football Focus. Below is a breakdown of his stats going back to the 2008 season.
All of these stats are for Guards who have started at least 25% of snaps for their teams in the respective years. They're also rankings rather than the PFF grades because I think that's more meaningful.
Overall Pass Blocking Run Blocking
2008 - 57/74 55/74 52/74
2009 - 75/84 34/84 83/84
2010 - 82/82 76/82 82/82
2011 - 46/78 25/78 69/78
2012 - Missed season due to injury.
2013 - 80/81 65/81 81/81
Now obviously PFF stats aren't perfect and perhaps its hard to grade linemen very accurately (seeing as Joseph somehow managed to make the pro bowl twice during that time), but these numbers at least give an idea of how Joseph has performed. He's one of the worst run blocking guards in the league and has been so his entire career and while he's had two seasons where he's been above average in pass blocking that doesn't come close to warranting his salary.
I think the only conclusion is not that Davin Joseph has had a down year because of his injury but that he's gotten even worse due to the injury from a pretty terrible baseline. With a 6 million dollar salary in the coming season it seems obvious to me that the Bucs should cut Joseph and draft a guard or sign one from free agency. It could hardly get any worse.