ST. LOUIS -- While the 2022 season has certainly been a frustrating one for Cardinals right-hander Jack Flaherty, it hasn’t been a total loss, according to manager Oliver Marmol.

“There's been growth, not just in the physical sense of, like, pitching, but in the preparation and mentality of how he's approaching it,” Marmol said before Flaherty’s much-anticipated return from the injured list Monday. “Being injured sucks, especially when you're an ultra competitor who knows that when [you’re] healthy, we're better. And when you have a tough time getting healthy, the frustration builds. So there's been a good bit of growth in his overall development and mentality, and he's approaching it from a team aspect and this isn't about Jack. He knows, like, ‘Man, if I get healthy, I can help the club.’ It's been good to see.”

Getting healthy has been the problem. Flaherty sandwiched three short starts in between two lengthy IL stints while battling a right shoulder injury.

While it wasn’t the dominant pre-COVID-19 Flaherty the team was hoping would anchor the rotation at the beginning of the season, his start in the Cardinals’ 6-0 loss to the Nationals on Monday afternoon at Busch Stadium finally offered a glimpse of optimism.

Flaherty gave up one run on six hits and one walk in a season-high five innings. He struck out six, and 59 of his 91 pitches were strikes.

“Jack was encouraging,” Marmol said after the game. “I thought he did a nice job. It looked good. It was promising. The fastball played, the velo was there. The shape of the other stuff was also there. The command [was] in and out, but it's only going to improve from here.”

Flaherty allowed at least one baserunner in each of his five innings. The lone run he allowed came in the third inning off a Lane Thomas ground-rule double that scored CJ Abrams. Flaherty responded by striking out the next three batters to limit the damage.

Flaherty once again showed the ability to make instant adjustments.

“The name of the game is making adjustments,” Flaherty said. “I put myself into some bad counts there and really had to make pitches, kind of made everything harder, but being able to make those adjustments pitch to pitch is really important.”

Back-to-back singles to start the fourth put Flaherty in another jam, but he struck out Josh Palacios on a 96.6 mph fastball and got Abrams to fly out to escape.

“You pitch with the way the game goes,” Flaherty said. “There are certain times in the game when you really got to make pitches in situations and leave those runners out there and leave a couple guys on base, and I was able to execute when I needed to. You just like to see it a little earlier so you don’t get into those spots.”

Flaherty found himself with runners on first and third and one out in the fifth, but he retired Luke Voit on a shallow fly to center and Keibert Ruiz on a fly to right.

“I thought he controlled his emotions well,” Marmol said. “I thought his poise was good. He made adjustments as the game went on. You could tell he was kind of battling the fastball a little bit, but [he] commanded it well enough. Leadoff man out, one out of five innings, but he was still able to kind of navigate through that.”

The hope is Flaherty can build off the start. A healthy Flaherty can deepen a starting rotation that has sparked heightened postseason aspirations amid a 25-8 run since August 1.

“He looked great out there, glad he's healthy, and hopefully that'll continue,” Cardinals first baseman Paul Goldschmidt said. “It's going to take all of us to accomplish any goals we have, and we're going to need everyone.”

Now Flaherty’s frustration is turning into excitement.

“To be in the spot that we’re at and [have] the chance moving forward to make a run at this thing … I’m glad to be a part of it,” Flaherty said.

Nationals starter Aníbal Sánchez loaded the bases in the first inning, but he got out of the jam by striking out Albert Pujols and getting Corey Dickerson to line out. Sánchez allowed just two hits in his five innings.

Washington broke the game open by sending 10 to the plate in a four-run sixth inning. All of the runs were charged to Andre Pallante, who retired just one batter but was victim of a lot of soft contact.

“Nothing you can do about that,” Marmol said. “A chopper, swinging bunts, it is what it is.”

Yadier Molina started his 2,098th game at catcher, moving him ahead of Carlton Fisk for second-most all-time.