15846558-standard.jpg

Defensive tackle Nick Fairley was enjoying a career season with Detroit until suffering a sprained knee in Week 8. He's now signed an incentive-laden deal with St. Louis.

(Melanie Maxwell | MLive.com)

PHOENIX -- Nick Fairley was drawing interest from the Cincinnati Bengals. He was drawing interest from the New England Patriots.

And he was drawing interest from the Detroit Lions -- though maybe not as much as one would expect, given Detroit had already lost its other starting defensive tackle. Some guy named Ndamukong Suh.

Fairley eventually signed with the Rams for a reasonable $5 million, though his deal includes another $3 million in possible incentives according to ESPN.

Why didn't the Lions do more to try to keep their former first-round pick?

"We're kind of looking at our situation, what fits, what suits us at this point in time," coach Jim Caldwell said last week. "Taking all things into consideration, we just thought it was obviously one of those situations where it didn't work.

"We decided to go elsewhere, and those kinds of things. Nothing personal."

Fairley was a tremendous talent for the Lions when healthy and motivated -- as talented as Suh, players and coaches liked to say. But he was rarely in peak form during his four years with the team.

So Detroit tried to incentivize him to get into shape by declining his 2015 option, which turned last season into a contract year. Caldwell later benched Fairley in the preseason, when his weight and effort were out of order.

And that's when Fairley finally turned it around, going so far as to hire a personal chef. The pounds spilled off him, until finally he was sub-300 for the first time since his days mauling quarterbacks at Auburn.

He turned in perhaps his most consistent eight weeks of football with the Lions, notching three QB hits, 17 QB hurries -- which was second among the league's defensive tackles at the time, according to ProFootballFocus -- and one sack.

But Fairley sprained his knee in that Week 8 game in London against the Falcons -- a victim of some friendly fire, with Suh colliding into him -- and did not play again despite an intense rehab regimen.

The Lions seemingly had little interest in bringing him back after the season, though general manager Martin Mayhew dispelled that notion at the owners meetings.

"I was in dialogue with (agent Brian Overstreet) throughout that entire process about Nick," Mayhew said. "I'm really hopeful he's turned a corner. I saw some really positive things from him during the season, and I'm hopeful he'll be able to turn the corner."

The Lions have replaced Fairley and Suh by trading for five-time Pro Bowler Haloti Ngata and signing restricted free agent Tyrunn Walker away from the Saints. Caraun Reid, entering his second year, is the backup.

[Related: How the Lions traded for Haloti Ngata | How the Lions signed Tyrunn Walker]

Detroit needs to acquire another defensive tackle, and could do so early in next month's draft.

"We're constantly looking," Caldwell said. "We're constantly making sure we're making improvements as we go along, and we do think the first two moves we made were significant.

"We'll see what happens."

-- Download the Detroit Lions MLive app for iPhone and Android

-- Follow Kyle Meinke on Twitter

-- Like MLive's Detroit Lions Facebook page