ALLEN PARK, Mich. -- Detroit Lions general manager Martin Mayhew regrets that he failed to have a backup plan in place this season in case running back Jahvid Best wasn't cleared to play.
As a result, the Lions lacked the type of playmaker in the backfield who could produce explosive running plays.
"Probably the biggest mistake that I made last year was counting on Jahvid Best to come back," Mayhew said Wednesday. "It's no knock on him. He did everything he could to get back.
"Based on the information we were getting medically, I felt very comfortable he was coming back. We did not have a real plan to replace him.
"In the history of the NFL, I can't think of a single player with a head injury, who was asymptomatic, that wanted to play, that wasn't allowed to play."
Asked to explain why doctors still haven't cleared Best, Mayhew said, "Legally, I can't explain it."
Mayhew won't take the same approach into next season, that's for sure.
"I'm not inclined at all to think it's going to work out," he said of Best's status. "I'm not at all inclined to rely on his return at this point."
Mayhew also conceded that he might have overestimated the talent the Lions had returning from a 10-6 team when they decided to bring back 21 of 22 starters.
"I think that's quite possible," he said. "If you look at our defense, who played better than they played last year? Of the 10 starters we brought back, probably Ndamukong (Suh) was the one guy who played noticeably better.
"Some guys flat-lined. Some guys were injured or didn't play as well. I don't know if it's overestimating the talent, but we didn't get the performances. The individual performances make the unit better and we didn't get the individual performances."
The priority this offseason, it's clear, will be to try to add more playmakers on the defense, particularly in the secondary.
The Lions forced only 17 takeaways while finishing 4-12 and losing their final eight games. A year earlier, they had 34 takeaways.
They also scored seven defensive touchdowns in 2011, zero in 2012.
"We need impact players, especially on the back end of the defense," Mayhew said. "We need guys that can impact the game. We've got a lot of guys that line up right, that know what their job is, but they don't impact the game.
"We need interceptors. We need the defense to sack the quarterback. We need guys that cause fumbles, guys that make plays on third down. Those are the kind of guys that can change the game for us.
"The turnover ratio was really out of whack. A lot of it is because we didn't get any. Our guys on the back end didn't make enough plays."
Mayhew admitted it will be "a challenge" to find those impact players for 2013, but it appears that will be a point of emphasis in next April's NFL Draft.
The Lions plan to try to renegotiate and extend the contract of quarterback Matthew Stafford during the offseason. Stafford is currently signed
"We'll free up some cap room doing that hopefully," Mayhew said.
... Receiver Titus Young, who didn't play the final six weeks for disciplinary reasons, returned to the Lions' practice facility Wednesday for a physical. Young, who was accompanied by his parents, was hampered by a knee injury throughout the season.
"I had a great conversation with him," Mayhew said. "He met with Jim (Schwartz) briefly."
As for whether Young will return to the team in 2013, Mayhew said, "I think it's hard to say right now. There's a lot that has to happen between now and then."
Mayhew indicated a decision might not be made for three or four months. Young must win back the trust and respect of his coaches and teammates for any chance of returning.
"If it was just based off this year, you might not consider bringing him back," Mayhew said. "But if you go back to 2011 ... he's demonstrated the ability to be a very productive player in this league.
"He's shown that he can be a good teammate. He's also shown that he can be difficult to work with. We'll figure it out."
... Mayhew said the Lions don't plan to use the franchise tag to lock up one of their free agents for 2013, the way they did in 2012 with defensive end Cliff Avril. The one-year tag assures a team of keeping an unrestricted free agent, but it comes at a high price financially.
On returning for 2013 with Schwartz, despite rumors that they could be on the hot seat: "As far as I know, we're going to be back. I've spoken with (owner) Mr. (William Clay) Ford, spoken with Bill (Jr.). We talked about our plans going forward. We're certainly working on getting things right."
... On whether he thinks Schwartz will make any other changes on the coaching staff other than the three departures confirmed last week (receivers coach Shawn Jefferson, running backs coach Sam Gash and offensive line coach George Yarno): "I don't think so. I think it's just those three."
... On the reaction from the Fords: "They want answers."
... On whether there's a sense that he and Schwartz have one more year to get things fixed: "That's the nature of the NFL. You have to win. Any time you only win four, you better have a sense of urgency that you better get it turned around quickly. We certainly have that sense of urgency and a high level of concern."
... On a report that his relationship with Schwartz is strained: "There's been no change in our relationship since 2009 when he got here. ... It is good."
... On his reputation for always drafting receivers: "I'll keep loving them. I've got to pick them better."