Detroit Lions kicker Jake Bates has been fairly productive through his first two NFL seasons. He’s made 84.1 percent of his field-goal attempts, plus has converted on 95.9 percent of his extra-point tries.  However, it wouldn’t be surprising to see Detroit general manager Brad Holmes bring in another kicker to compete with Bates ahead of training camp.  With that said, here are four kickers the Lions could still pursue this offseason.  Graham Gano   Gano is a savvy vet who has made 83.8 percent of his field-goal attempts during his 16-year NFL career.  In his final three years with the N.Y. Giants, though, he failed to play in a full season, and converted on just 29 of his 38 attempts (76.3%). While that is not exactly the mark of proficiency, he was successful on nine of his 10 field-goal tries last year before being placed on injured reserve with a herniated disc in his neck.…