The Twins' intention to avoid putting Tyler Mahle on the injured list ran into a harsh reality about modern baseball and pitching usage: There's no room on the roster for a player who can't play.

"Having a spot for 10, 11, 12 days that isn't being used and isn't benefiting us at the moment is hard. It would be tough to get through that," Twins manager Rocco Baldelli said, particularly under MLB's new rule limiting teams to 13 pitchers. "That's a small part of it. … Just the fact that there's an unknown [about when he'll return] makes us make this decision."

Mahle, who left Wednesday's start because of shoulder fatigue, says he feels no pain in his throwing shoulder, but the Twins are worried about recurrence, particularly since the righthander spent 15 days on the injured list with Cincinnati in early July, two weeks before being traded. He returned to that list Saturday, with lefthander Devin Smeltzer recalled from Class AAA St. Paul.

"[Mahle's] doing as well as we could have hoped. This is just a wise and forward-looking move," Baldelli said. "Just because he's able to pitch doesn't mean it's the version of Tyler we all want to see."

Mahle will not throw again until later this week, Baldelli said.

Smeltzer has made 12 starts for the Twins this season and another nine for the Saints, but the manager said that, though the Twins have not yet settled on a starting pitcher for Mahle's scheduled start in Houston on Tuesday, Smeltzer will more likely be used in the bullpen this weekend.

The Rangers' lineup is loaded with left-handed hitters, and until Saturday, Caleb Thielbar, who pitched Friday night, was the lone lefthander on the Twins' current roster.