Brantley, who has been dealing with the back issue since February, played in Cleveland's home opener on Friday after sitting out the previous two games.
General manager Chris Antonetti reportedly said that an MRI on Brantley showed that everything was "sound structurally."
After facing Detroit on Sunday, the Indians get a day off before beginning a two-game series with the Chicago White Sox in Cleveland.
"His back spasms flared up toward the end of the game last night," Indians manager Terry Francona said on Saturday, according to the Associated Press. "I probably got a little carried away yesterday when Michael told me he was ready to play. I probably should have said, `No, you're not playing.' He'll want to play, but I think this is the smarter way to handle it. I just want him to be himself."
Brantley recorded a .327 batting average with 20 home runs and 97 RBI last season. The 27-year-old earned his first All-Star nod and finished third in the AL MVP voting.
SI.com projects the Indians to finish with the fourth-best record in MLB.