Is the veteran offensive tackle overrated? Of course not. In a league where defenses continue a de facto arms race for pass rushers, teams will also pay a premium for offensive linemen. The first round of this year's draft is a good reminder of that. However, recent trades involving Saints OT Jammal Brown and St. Louis Rams OT Alex Barron fetched much smaller returns than some would have initially believed and may signal the emergence of a more rational offseason market for offensive linemen. 

In case you haven't noticed, bubble bursting has been a hot trend for a few years now. Why should the housing market have all the fun, when teams were willing to create stimulus packages of their own for the chance to nab an established offensive lineman? Let's look at the evidence.

Fans and pundits alike knew Alex Barron was on the trading block when the Rams issued the oft-penalized tackle a first round RFA tender that asked only for a second round pick for compensation. Obviously, no teams were willing to give up a second rounder for Barron. Few teams even bothered to explore a trade for a starting left tackle with a spotless injury history until the Cowboys sent backup linebacker Bobby Carpenter to the Rams in exchange for the 2005 first round pick. 

The Saints traded Jammal Brown for a conditional third round pick that could very likely be a fourth round pick, depending on how well Donovan McNabb performs in a convoluted deal. A third round pick in and of itself isn't a bad deal for a 29-year-old Pro Bowl offensive tackle, even for one coming off a season lost to injury. Still, there was a time when Brown was linked in trade talks (to the Rams no less) as part of a deal for a first round pick. 

2008 was the high water mark for the offensive lineman bubble, when offensive guards Alan Faneca and Jacob Bell signed huge deals. Faneca was released by the Jets this spring, who ate his contract in favor of Vladimir Ducasse, a second round pick in this year's draft. Faneca ended up with the Cardinals on a one-year, $2.5 million deal. After getting healthy (mostly) and gaining weight, Bell did a lot to shake off the bust label he earned after one season, but he's still a long way from playing up to his contract. 

Last offseason veteran offensive tackles went to other teams and ended up in the dustbin, see Levi Jones and Orlando Pace. The Eagles acquisition of Stacy Andrews didn't do anything positive for big fee agent contracts to offensive linemen. The exception last year was the Rams signing of C Jason Brown played up the expectations his contract established. 

Free agent additions of offensive linemen slowed considerably this season. So what burst the bubble?

Teams value their offensive linemen and don't let them leave. Offensive linemen are still getting big contracts (e.g. Jahri Evans), but they're getting the bucks from their teams who don't want to replace the bricks and mortar of their foundation. 

Drafting offensive linemen is the preferred route. Yes, Jason Smith's contract costs more than a free agent, but teams get younger, relatively healthier offensive linemen. When teams don't let their blockers leave in the prime of their career that leaves teams little choice other than going to the well in April for their cornerstone offensive linemen...unless they want to spend big bucks on an older guy. 

The price of older offensive linemen is down. Fetching a bounty via trade rarely happens in the NFL as it is, since teams don't usually trade players in the prime of their career like you see in Major League Baseball. So players like Barron and Brown are getting shipped off as extra parts that teams would be unlikely to keep on the roster given the costs of keeping them as backups. Still, it's surprising to see two players, at such a premium position, dealt for returns that seem small. 

Offensive linemen hitting the free agent market will still fetch big contracts, simply because of the law of scarcity. However, the irrational exuberance that once handed out elite-level contracts to middling starters or aging Pro Bowlers seems to have passed. Lesson learned...for now.