Returning at the halfway point of the regular season, Thomas was faced with a possible medical redshirt or being able to play.
To play was the decision made by Thomas and the Spartans coaches.
"I just felt like I could help my team out a lot and just if I'm good to go, why not play? That was a decision me and my coaches have made. I feel like I can help my team to the Rose Bowl."
Thomas, who suffered an undisclosed injury that kept him out for fall camp, said he can't really say where he is health-wise.
"I am going pretty good out in practice," he said. "All of the drills, how I'm moving, my agility, my speed, things are looking fine."
While spending the early part of the 2013 season and watching the Spartans get off to a 5-1 start, Thomas said it was tough to see the team progressing and not being a part of it.
"It was tough after a great spring and I had high hopes and everything," he said. "I can't question God. Everything works in God's hands."
Still, the 6-foot-3, 305-pound defensive lineman said he gained a lot of maturity in his absence.
"I think I'm maturing a lot, just learning the playbook inside and out and just getting physically strong and mentally strong as well," he said. "By me sitting out for the first half of the season, I think that just grew. Mentally, I'm just stronger. That helped me a lot."
Thomas appeared on the MSU depth chart for the first time this season Tuesday at defensive end.
Coach Mark Dantonio said putting Thomas in at end instead of defensive tackle will make it a bit easier for him to work back to the tackle spot.
He also said Thomas could have played against Indiana last Saturday, but it didn't fit with the flow of the game.
"We need to get him some live reps, active reps," Dantonio said. "I thought he could have possibly played on Saturday, but the way the game just went with the whole nature of it, we decided not to play him. ... It's time now. I think he needs to play."