Lions salvage Chris Houston from '12 mess

We've been discussing the Detroit Lions' pending defensive overhaul for some time, a shift they've advanced through free agency by inviting two players -- safety Glover Quin defensive lineman Jason Jones -- for first-day visits. But the cornerback position is difficult to upgrade en masse, so it made sense for the Lions to prioritize the return of starter Chris Houston.

The Lions' five-year agreement with Houston, struck Wednesday morning, doesn't solve the Lions' deficiencies in the secondary or even at cornerback. It was, however, a wise move to salvage the most reliable and skilled member of what was by all accounts an underwhelming group. As the chart shows, the 2012 Lions were the NFL's worst pass defense on throws outside the numbers -- the typical domain of cornerbacks -- according to ESPN Stats & Information.

The 2013 market contains a glut of veteran cornerbacks, but Houston, 28, was surely one of the best available if your took a multiple-season horizon. Coach Jim Schwartz signaled his affection for and interest in bringing back Houston during the NFL scouting combine last month, noting the Lions used him as a true No. 1 cornerback last season to defend opponents' top receivers for the first time.

"Corners are tough to find in the NFL," Schwartz said, "and Chris started out the season hurt. He had an ankle sprain coming into the regular season and missed the first couple of games. You realize how much you miss a guy when he's not out on the field. Chris added some things to his résumé that he really didn't have before. There were a few games that he matched No. 1 wide receivers, guys like Andre Johnson, Brandon Marshall, people like that. That was something that we really hadn't used him for, he really hadn't done before.

"But he's played some quality football for us and has worked on some things early in his career that had been weaknesses. He's a vet, he's a pro, he's a guy that's been productive for us."

The key to the Lions' defensive improvement will be surrounding Houston with more players of similarly competent skills. Quin and Jones are their early targets, and they have also re-signed linebacker DeAndre Levy and retained defensive end Willie Young. That could mean the departure of safety Louis Delmas, and perhaps defensive end Cliff Avril and linebacker Justin Durant as well, but still leaves the Lions a few cornerbacks short.

The reality of the cornerback position is that you can add one or maybe two decent players in one offseason. If you already have one, it makes sense to keep him rather than dig a deeper hole.