ATLANTA -- The Pirates are down to three healthy starting pitchers.

Before Monday night’s series opener at SunTrust Park, Pittsburgh placed right-hander Jordan Lyles on the 10-day injured list with left hamstring tightness and recalled reliever Montana DuRapau from Triple-A Indianapolis.

Lyles has been bothered by a sore left hamstring for about two weeks. He exited his start on May 28 in Cincinnati after four innings due to discomfort, and head athletic trainer Bryan Housand came out to the mound to check on Lyles during Saturday’s game at Miller Park.

“Just tried to battle through it the last few outings. Wasn’t very efficient during those outings,” Lyles told reporters on Monday afternoon. “It was -- I wouldn’t say minor, but we’re going to make sure it doesn’t turn into anything major.”

Pirates manager Clint Hurdle said he thought Lyles’ hamstring issue affected his delivery and pitch execution in his last start. Lyles needed 92 pitches to get through three innings, but said he felt fine after the game.

“I had all the confidence in the world that I could be still effective. Obviously that wasn’t the case,” Lyles said. “Sometimes you’ve just got to be smart and take a little breather, heal up and get back to where you were previously.”

Now, the Pirates have to fill two holes in their rotation. They don’t have a starting pitcher listed on Wednesday against the Braves, and they will need to find someone to start on Saturday now that Joe Musgrove won’t be available to pitch that day.

Musgrove threw 18 pitches before he was ejected along with manager Clint Hurdle and Braves third baseman Josh Donaldson in Monday’s 13-7 loss. That forced Alex McRae into long relief duty and put Musgrove in line to start Thursday’s series finale. The Pirates entered Monday thinking they’d need one starter for Wednesday and another for Thursday, but Musgrove’s early ejection led to a change of plans.

Left-hander Steven Brault started Sunday’s series finale in Milwaukee, so he won’t be properly rested to pitch until Friday. Right-hander Chris Archer is scheduled to pitch on Tuesday night. Musgrove is the Bucs' only other healthy starter. Right-hander Trevor Williams is expected to make a Minor League rehab start later this week after throwing a four-inning simulated game on Saturday.

Pittsburgh’s rotation is now without Jameson Taillon (right elbow flexor strain), Williams (right side strain) and Lyles (hamstring) in addition to depth options like Chris Stratton (right side discomfort), Rookie Davis (right middle finger blister) and JT Brubaker (right forearm strain). The Pirates parted ways with right-hander Nick Kingham, who started four games this season, by designating him for assignment on Saturday.

General manager Neal Huntington acknowledged on Sunday that top prospect Mitch Keller is a candidate to start Wednesday’s game. The Pirates experimented with an opener earlier this season, but Hurdle essentially ruled out that idea on Monday.