Less common for players who have taken that comeback trail is the opportunity to get back to their old role. Yet with Spring Training games about to begin, Thomas has a real chance to become a Tigers outfielder again.
"If you're asking me if he's in competition, you certainly have to consider him," manager Jim Leyland said of Thomas Tuesday.
He has been there before. He went from non-roster invitee to the Opening Day roster in 2008 as a replacement for the injured Curtis Granderson, played in 102 games with Detroit in 2009 and lost a hard-fought battle with Don Kelly for the final roster spot the following season. That was before he was hurt.
He missed the start of the 2010 season at Triple-A Toledo with a hamstring injury, but it wasn't until he had come back that his knee trouble became apparent around his meniscus. He underwent microfracture surgery to repair it in mid-June.
For a lot of athletes, that starts a year-long rehab process to get back to action. Thomas not only beat that, he was working out without restriction by the beginning of March. He wasn't ready to compete for a roster spot, but that wasn't the point. Thomas and the Tigers wanted to get the process going.
That doesn't simply mean playing. It means having good days and bad, setbacks and milestones, disappointments and highlights. For Thomas, it meant a fair share of hurdles, not all of them purely physical.
"It wasn't easy," he said. "I had a decent spring, but [opponents] weren't throwing many curveballs. They weren't mixing it up a whole lot. You get [to the regular season], then they're starting you off with curveballs or changeups. I was probably real jumpy, wanting to do really well at the beginning and just trying to force it instead of just letting it happen."
As Thomas put it, he was trying to prove himself -- and justify his adrenaline -- with a five-run homer.
"Trying to get four hits in one at-bat wasn't working out," Thomas said. "You have to be patient, play every day."
At the same time, he said, he had a hesitation in his game.
"It just felt like something was missing," he said. "It's like I knew what was coming. I saw the pitches, but something wasn't clicking."
On June 22, Thomas was batting .203, while watching Brennan Boesch and Casper Wells play in Detroit. They were a level behind him a few years earlier. So was Andy Dirks, a similar style of player who made an impression on the Tigers last spring.
A .284 average in July was the first sign of a rally, though he still had more strikeouts than hits. He went into the final week of the season with a .234 average, thanks in part to a fractured left finger that hampered him in August and cost him the second half of the month. Then came his closing shot.
For his final four games, Thomas showed the multi-tooled talent that won over the Tigers a few years ago. He went 10-for-16 with a home run, three RBIs, two runs scored, two strikeouts and four stolen bases.
With that, he hit .309 with an .843 OPS after the All-Star break. For the year, he batted .253 with 12 homers, 53 RBIs and 20 stolen bases. More important, he felt like himself.
"After the All-Star break, that's when it really started going a lot better," Thomas said. "I finished really strong. I was running good, stealing bags, hitting the ball all over the ballpark. I felt great. I felt like I was me again. That first half was rough."
Just as important, the Tigers saw the same thing. That might have kept him on the 40-man roster going into the offseason. Moreover, team officials said he'd come in with a chance to compete for an Opening Day roster spot.
"His swing is showing no side effects of any past injuries or anything," Leyland said. "He looks really good right now. You know, he's a very athletic guy and a very good tools guy -- power, speed, good outfielder. My reports basically were that he started to come on at the end pretty good. Sometimes it takes time to get over those injuries."
It doesn't always work that way, even with the surgery cases that are successful. Grady Sizemore and Carlos Guillen both eventually made it back, but have battled other injuries since. Victor Martinez could face similar challenges when he makes it back next season, though his surgery came from the same specialist who operated on Thomas.
With Thomas, Detroit could well have the best-case scenario. And if Delmon Young spends some games at designated hitter, opening up left field, the Tigers could have Thomas back in a role.