DETROIT — The Detroit Lions have tried to make a big splash in free agency before, only to discover that there was no water in the pool. But this feels different.

The signings of Kyle Vanden Bosch and Nate Burleson and the trade for Corey Williams make sense, not just in a vacuum but in the context of what the Lions are trying to do. Finally, there is a plan.
Now, I don’t know if the plan will work. With the Lions, skepticism is not just healthy, it is mandatory. But let’s look at why the Lions made these moves.
I’ve written this before, but what made the Lions so awful the past two years — as opposed to very bad — is they didn’t do anything well.
Even bad teams usually have strengths. Maybe they have a good running game but an awful defense and no quarterback. Maybe they have great special teams. Something. The Lions, on the other hand, went into a lot of games the past two years without any clear advantages over their opponents. That is how you go 2-30.
The Lions desperately needed a No. 2 receiver to help Matthew Stafford and Calvin Johnson, the most important players on the team. They also need a running back.
They probably weren’t going to get immediate receiving help in the draft. They can potentially get a running back in the second or third round. And signing free-agent running backs is risky, because by the time NFL running backs hit free agency, they already have a lot of miles on them. So it made more sense to sign Burleson than one of the big-name running backs available.
As for Vanden Bosch: $26 million sounds like too much for a 31-year-old defensive end who had three sacks last year. But since the Lions are paying $10 million up front (in a year with no salary cap), it doesn’t look like a franchise-crippler.
Lions coach Jim Schwartz coached Vanden Bosch in Tennessee, so that was a factor there. (I was amused by the story that Schwartz was waiting outside Vanden Bosch’s house in Nashville, Tenn., when free agency began Thursday night. What an amazing coincidence that Schwartz knew Vanden Bosch would be home, instead of visiting family or something.)
But I think this goes beyond Schwartz’s fondness for Vanden Bosch. Schwartz had his greatest success in Tennessee with a deep, powerful defensive line. He always had a fresh, talented defensive lineman to put in the game and rarely blitzed. If you can create pressure without blitzing in the NFL, you are on your way to a great defense.
Naturally, Schwartz would love to build the same kind of defense in Detroit, especially since Lions cornerbacks have not broken up a pass since 1993. So what do the Lions do? They grab Vanden Bosch to play defensive end. They trade for Corey Williams to play defensive tackle.
And, most likely, they choose another defensive tackle (either Ndamukong Suh or Gerald McCoy) with the No. 2 pick in the draft to anchor the line.
Meanwhile, defensive coordinator Gunther Cunningham loves defensive ends who tie up the line of scrimmage, freeing linebackers to make plays. (All defensive coordinators like that, but Cunningham emphasizes it more than most.) Vanden Bosch is a big, physical defensive end who can do that.
The 2010 Lions are not going to be great. But they can be competitive. With a revamped defensive line and more offensive weapons, they should at least have some strengths. In Detroit, that is progress.