Martinez continues to work toward being able to make that return, but reports from Tigers head athletic trainer Kevin Rand don't bode well.
"He's just doing single leg strengthening until he reaches a point where they feel comfortable starting a running progression," Rand said. "He's basically running out of time."
Martinez, who tore his left anterior cruciate ligament during offseason workouts in January, underwent microfracture surgery later that month. He was initially expected to have no chance to play this season and undergo reconstructive surgery in April, but the doctor treating him decided his knee healed enough to not require it.
So the 33-year-old instead underwent a less serious procedure to assist in the healing process, thus restoring some hope for him to play this year.
"We were hopeful," Rand said. "I was hopeful at the point in time at the end of July that he would test out a little bit better than what he did. Unfortunately, you just don't know in those instances."
Martinez hit .330 with 103 RBIs for Detroit in 2011. He is signed with the club through '14.
"To me, I'm looking at this from the standpoint -- we have 2013, 2014," Rand said. "I'd love to have him here. But by the same token, you can't put him at risk for those two years."