Scott Baker is taking over in the rotation for Ross, who was 1-4 with a 4.78 ERA in nine starts. Baker will start Friday at Detroit, with lefty Ross now available as a reliever.
''We know he can pitch out of the bullpen,'' manager Ron Washington said Tuesday. ''We haven't totally gotten away from Robbie Ross being a starter. It's just that right now we've got to get him in a position where he can have some success.''
General manager Jon Daniels said Scheppers, the team's opening day starter, will be a reliever again when he comes off the disabled list.
Scheppers was 0-1 with a 9.82 ERA in four starts before going on the DL on April 18 with right elbow inflammation. He was scheduled to throw live batting practice at Double-A Frisco on Wednesday, start a rehab assignment this weekend and could be back in about two weeks.
With Yu Darvish and Matt Harrison both starting the season on the disabled list, Scheppers became the first pitcher to make his first major league start in a season opener since Fernando Valenzuela in 1981 for the Los Angeles Dodgers.
Scheppers was 6-2 with a 1.88 ERA pitching primarily in the eighth inning last season, when his 76 appearances were the most ever for a Texas right-hander.
''Ultimately what it comes down to right now is we're just playing a little bit more conservatively, given the nature of some of the things going on, specifically with the injuries, not just to Tanner, but the club,'' Daniels said. ''We feel like he can probably be a successful starter, we know he can be a reliever, and a productive reliever, and we need production right now. ... We're going to take the surest bet at this point.''
The Rangers have a majors-high 13 players on the disabled list, seven of them pitchers.
Martin Perez was transferred to the 60-day DL on Tuesday, a day after surgery to repair the partial tear of his ulnar collateral ligament in his left elbow.
Harrison, who has a displaced vertebra after making only two starts in 2013, is facing likely surgery that could be career-threatening.
Baker pitched 5 1-3 innings in relief in his Texas debut May 7, before being designated for assignment. He went back to Triple-A Round Rock, but rejoined the Rangers last week.
Baker has started 162 of his 167 career games, and was 63-48 with a 4.15 ERA for Minnesota from 2005-11 before ligament replacement surgery in April 2012. The right-hander and made three starts for the Chicago Cubs last September.
''He's got experience. He's been out there trying to get 27 outs before. And we'll give him a shot,'' Washington said. ''That's where we are right now. Giving opportunities. We're going to give him an opportunity.''