Sammy Solis is back on the disabled list, this time with left shoulder inflammation. (Getty Images)

DENVER — Koda Glover heard he was coming back to the big leagues around 11:30 p.m. Tuesday night, just after the Syracuse Chiefs wrapped up a 4-3 loss to the Mud Hens in Toledo. Not five hours later, he was headed to the Detroit airport for a flight to Denver, where he arrived about four hours before game time.

“I thought I didn’t sleep the first time [I came up],” Glover said with a smile. “This time is even worse.”

The Nationals needed Glover to hurry to Colorado because Sammy Solis had to fly home to Washington for an MRI exam on his left (throwing) shoulder, in which he is suffering from “inflammation,” according to the team. Solis’s velocity had been down in recent outings, and he reported to work after Monday night’s outing feeling “very sore,” according to Nationals Manager Dusty Baker.

“He’s not doing as well as we had hoped,” Baker said. “…that’s why he wasn’t available last night. He’s just sore. He’s had a number of small little injuries that he’s pitched through, so we sent him back to take an MRI this morning.”

Baker said he didn’t know when Solis starting experiencing the trouble because he “doesn’t say much,” though he acknowledged Solis’s injury history. The Nationals converted Solis from starter to reliever two years ago in part because they hoped it could allow him to stay healthy. The 28-year-old was on the disabled list once already this season with knee trouble, though Baker said it is often tough to tell when Solis is hurt.

“He doesn’t complain, so how do you read someone who doesn’t complain?” Baker said. “I wish everybody would be like that — not complaining. It would be a much better world. He said he’ll be okay, and we’re hoping the MRI comes back clean.”

Without Solis, and with Felipe Rivero gone to Pittsburgh in the Mark Melancon deal, the Nationals have one left-handed pitcher in their bullpen, which contained three of them for most of the season.

“That changes a lot,” Baker said. “Depending on Sammy’s health situation, depends on what we have to do. It’s tough just with one lefty, especially because everybody had a role and a job at the time.”

That one is veteran enigma Oliver Perez, who has allowed 11 of the last 20 batters he has faced to reach base — and who will now be relied upon more, and in bigger situations, than ever. In five August outings, Perez has allowed four walks, four hits and four runs with one strikeout.

“We realize he’s struggling. You don’t have to tell him. He knows he’s been struggling some,” Perez said. “They’ve been working on some things. Mike Maddux and him have been working on some stuff in the bullpen, but you can’t work too hard, otherwise you’ll leave it all in the bullpen and not be able to take it into the game. They’ll figure it out.”

Perez has been prone to long lapses in command in his career, and his herky-jerky, unorthodox delivery requires more synchronization than simpler motions do. Baker compared him to first baseman Ryan Zimmerman, whose swing involves a high leg kick and pronounced bat waggle, all of which must work in unison for him to be successful. Recently, Perez has been unable to find his rhythm.

Baker pointed out that Glover has handled left-handers well this season, and in fact, he has held lefties to a .161 average during his Class AAA stint this season, right-handers to .216. Since Glover returned to Syracuse after his two impressive scoreless innings in late July, he has gone more than an inning in five of his seven outings. He has thrown 6 1/3 innings in August, allowed no hits and struck out 12.

“I knew I had some more stuff to work on before I came back up. That’s what we did,” Glover said. “I got with the pitching coach, we tuned some stuff up, and made a couple adjustments. I think it was beneficial.”

Glover said the main adjustment involved pitch sequencing — finding ways to rely less on his high-90s fastball and mix in his curveball and change-up more effectively. While Glover’s fastball is the pitch that got him to the big leagues in the first place, “these guys can hit it,” he said Wednesday.

“Knowing that and being able to adjust,” Glover said. “That was the biggest thing.”

By the time Solis is eligible to return from the disabled list — and whether or not he will be ready to do so then is another question — rosters will be expanding. As such, Glover may get a more extended chance at the majors than he did before, perhaps even through September if things go well — and especially if he carries his success against left-handed hitters into the majors.