The Oakland Raiders are about to trade for Matt Schaub, Adam Schefter reports, giving up a late-round pick and a massive salary for one of the worst quarterbacks in the NFL, last season. But then, Schaub was a pretty competent starter in previous years. Why would they take that gamble, instead of just drafting one of the top passers? For the same reason the Tampa Bay Buccaneers signed Josh McCown: security.
The Bucs and Raiders want to win, now. The Bucs because they have the talent to do so, the Raiders because everyone's going to be fired if they don't start winning. These teams can't afford to have their seasons torpedoed because their quarterback is not up to snuff. They can't afford to start a rookie passer they overdrafted because of need. They certainly can't afford to gamble that the quarterback they like will even fall to them -- what do you do if you only like Blake Bortles, but the Houston Texans take him first overall?
It's the same reason why the Kansas City Chiefs traded for Alex Smith last year, and why the Arizona Cardinals traded for Carson Palmer: they didn't want quarterback to be the reason they lost games. And while the Chiefs gave up a minor bounty for Smith, this did mean they didn't have to hang their season on the likes of Geno Smith, E.J. Manuel or Mike Glennon. It got them a playoff berth, and only the second-biggest comeback in playoff history prevented them from doing more than that -- and Alex Smith was not why they lost, either.
Like the Chiefs last year, the Bucs and Raiders teams are in win-now mode. They're not rebuilding patiently, laying the foundations for long-term dominance. Those rebuilding teams can afford to gamble at the quarterback position (or any position, really). Instead, the Bucs and Raiders are looking for quick turnarounds, and a quick turnaround can't happen if you don't have a quarterback.
It comes down to this: if the Buccaneers and Raiders can't find an upgrade at quarterback in the draft, at least they'll have Josh McCown and Matt Schaub, instead of Mike Glennon and Matt McGloin.