When Kenyan Drake was 8 years old, Frank Gore tore his right anterior cruciate ligament in a practice for the University of Miami. When Drake was 9, Gore tore his left A.C.L. By the time Drake was 16, Gore had endured reconstructive surgery on both shoulders and was trying to come back from a broken hip.

Now 24 and entering his third N.F.L. season, Drake somehow finds himself competing with the 35-year-old Gore to be the starting running back for the Miami Dolphins.

It may seem impossible, but as Adam Gase, the head coach of the Dolphins, told reporters when asked about Gore’s prospects for this season, “I learned a long time ago: Never doubt him.”

Gore showed first-round talent in college at Miami but came into the league as a third-round pick in 2005 thanks to his injury history and 5-foot-9 frame. Should he rush for 76 yards this season — he has had at least that many in a single game 82 times in his career — he will pass Curtis Martin for fourth place on the N.F.L.’s career rushing list.