(Gene Puskar / Associated Press)

For the first time in nearly a month, the Nationals’ starting rotation is expected to become whole again. Ross Detwiler tossed 3 2/3 innings in a rehab game at Class A Potomac on Saturday and is slated to return from the disabled list for a start Thursday. Stephen Strasburg threw a simulated game Tuesday at Coors Field and said that he felt no tightness in his side, where he has dealt with a lat strain.

Strasburg threw 56 pitches in a simulated game, facing teammates Chris Marrero, Jeff Kobernus and Jhonatan Solano, and with trainers, Manager Davey Johnson and pitching coach Steve McCatty watching intently. Strasburg, who last pitched on May 31, is on track to return from the disabled list Sunday and start in Cleveland, Johnson said.

“I didn’t really feel like I threw at all,” Strasburg said. “I feel like my strength stayed there even though I missed a couple starts.”

The Nationals expect to call up right-handed starter Ross Ohlendorf from Class AAA Syracuse to make Wednesday’s start in Colorado, the day the Nationals need a starter. Ohlendorf is expected arrive in Denver on Tuesday night, Johnson said. This would mean rookie right-hander Nate Karns, who made three starts in place of Detwiler as he dealt with an oblique strain, would be sent back down to the minor leagues.

Johnson, however, said Karns would stay for now as the Nationals want to be sure Strasburg shows no ill effects Wednesday.

After Ohlendorf’s scheduled spot start Wednesday and Detwiler slated for Thursday, Johnson said he expects to start Gio Gonzalez on six days rest on Friday in Cleveland. Jordan Zimmermann is scheduled to follow on Saturday. For the first time since Detwiler exited his May 15 start, the Nationals’ starting rotation could return to normal.

“It’d be nice,” Johnson said. “I’ll wait until it happens. It’s getting close enough they’re all ready to go. It’ll be good.”