WASHINGTON -- Andre Pallante was back for the ninth inning on Sunday with a low pitch count and high ambition.

He pitched eight scoreless frames before heading to the final one with 93 pitches thrown. His manager, Oliver Marmol, wanted the rookie to have a chance at a shutout. Two light hits by the first two batters ended that chance, but the day opened eyes after Pallante finished with eight strikeouts, one walk and his fourth career win in the Cardinals’ 5-0 victory over the Nationals on Sunday at Nationals Park.

“That was an impressive outing for sure,” Marmol said. “Fastball played, slider was hard, late movement.”

Pallante has moved from the middle innings to later bullpen work to the mound in the first for 10 starts. He’s a 23-year-old rookie approaching a career high in innings pitched. The MLB Trade Deadline is 5 p.m. CT Tuesday. The Cardinals need to decide what his stretch run will look like, and Pallante’s pitching future could be tethered to the club’s ability to land further pitching help. St. Louis has been linked to Oakland right-hander Frankie Montas as it searches for ways to solidify a pitching staff while sitting just outside a playoff spot with 60 games remaining.

“It’s something over the next week we’ll re-evaluate and kind of figure out what our final number for him would be, plus or minus some,” Marmol said. “Stage it out and see where that lands. Plan this out all the way through the playoffs. That’s an exercise that will take place here shortly. …There’s still some moving parts.”

On Sunday, Pallante and his manager were pleased with the immediate results. His prior turn in Toronto delivered only four innings, with seven hits and three earned runs. In between, Pallante focused on his slider, which became a distinct weapon Sunday against the Nationals.

He threw it 27 percent of the time, well ahead of his 20.4 percent average coming into the game, to both left-handed and right-handed hitters. Pallante said his frequency increase to left-handers helped develop his feel for the pitch when throwing it against right-handers. The velocity was up a touch, too.

“I definitely was aggressive with it,” Pallante said. “I think throwing it against the lefties helped against the righties because I was throwing it more, so I was able to have better command. It wasn’t like, ‘Where did it go?’ Same with the curveball. That really opened up a lot of my stuff.”

Pallante said he is adjusting to big league hitters’ mentalities as much as he is rearranging his pitch sequences or usage. In the Minors, he said, it is important to throw strikes up to 0-2 counts because the hitters are less aggressive. In the Majors, the aggression shifts.

“They’re not trying to walk,” Pallante said. “They’re trying to hit the ball. Definitely a different animal in that batters are more aggressive, but also the batters are smarter. Felt like I had a learning curve, a little bit.”

Two things about his rookie impress Marmol:

“His ability to stay calm in the heat of the moment,” Marmol said. “Then two, his ability to apply things from his bullpen into the game. [Sunday] we saw a slider that was harder, sharper and tougher to hit. Lefties didn’t like it a whole lot.”

Marmol discarded any suggestions that the timing of Sunday’s dominance would influence what the Cardinals do with (or around) Pallante going forward. The righty's outing was a boost both for him and a team ending an eight-game, 10-day road trip after a middling July. What comes next for both remains up in the air.