Cliff Avril, an unrestricted free agent, is just one of several question marks for the Lions on defense.

 The defensive end said his chances of returning to the Lions are about 50-50 in an interview on the NBC Sports Network this week.

 Avril couldn’t reach a long-term deal with the Lions last offseason so he was franchised for a year at $10.6 million.

  While Avril has played mostly at left defensive end, last week GM Martin Mayhew said Avril is versatile enough to play either side.

“He can do a lot of different things, he’s a very talented guy. He’s got a lot of versatility,’’ Mayhew said.

 After the Lions released Kyle Vanden Bosch last week, certainly defensive end is a position of need.

 It’s just another reason the Lions need Avril back. He had 9.5 sacks, 35 tackles and a pair of forced fumbles last year and he’s just 26 years old.

While he hasn’t had to be a leader on the defensive line with Vanden Bosch and Corey Williams around, Avril definitely has leadership capabilities — much more than Ndamukong Suh or Nick Fairley.

 When he didn’t sign the long-term deal the Lions offered last year, he was betting on himself. Betting that he would have another good season.

 Was it a good bet?

 We will see.

 Mayhew said that Lions’ recent history has shown that for the most part they have been able to get back the players they want.

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