Daniels added that should Kluber be able to return this season he'd likely have to pitch out of the bullpen.
The right-hander left his start Sunday with shoulder tightness after throwing just one inning in his Rangers debut.
The club will now turn to Kolby Allard to fill the vacant spot in the rotation, Daniels said. Texas won't have to do that anytime soon, however, as they have four off days in the first three weeks of the season.
The Rangers were planning to skip Jordan Lyles' (their No. 5 starter) spot in the rotation to start the year but he'll now be asked to step in for Kluber.