(Photo by John McDonnell/The Washington Post)

Blake Treinen made a loop around the Nationals clubhouse this afternoon before batting practice, shaking hands with teammates and coaches. His teammates repeated the same refrain: We’ll see you again soon.

Thursday night, Treinen threw 60 pitches and soaked up 2 2/3 innings in a blowout. In 6 2/3 innings over three appearances, all since Saturday, Treinen allowed one earned run and struck out seven while allowing 10 hits and two walks. The Nationals feel Treinen still needs to improve his secondary pitches, but they salivate over his sinking, high-90s fastball.

“That’s a heavy fastball,” Manager Matt Williams said. “Not to put any pressure on anybody, but that’s a Verlander-esque fastball at 97, 98 miles an hour. Certainly, Justin Verlander is a polished pitcher and he has better pitches to go along with it – changeup, curveball, slider. But that fastball plays. It’s more of the same for him: make sure he works on his secondary pitches, and he’s able to start for us if need be. He can fill multiple rolls at any given time depending on need.”

The Nationals sent Treinen back to Class AAA Syracuse just six days after they summoned him to make his big-league debut. But they believe Treinein, who was sent down after a laborious week so the Nationals could recall a fresh arm in Xavier Cedeno, will make an impact in the majors again this season.

“The plan for him outside of the major league team is for him to start and build his innings,” Williams said. “Last night is an example of taking him to that limit, certainly. Didn’t want to do that, but for the health of the remaining guys in the bullpen, he was one of our long guys. What it means for him now is, he’d probably be shut down for two to three days at least. It also gives him an opportunity to get on his progression and get on normal rest. That’s why we made the move. He’d be unavailable for the next couple, three days, anyway.”

Cedeno likely will hold a place until the Nationals can recall Barrett, whom they optioned in order to add Treinen as a fresh arm. Barrett was optioned Saturday and, by rule, must spend 10 days in the minors before the Nationals can recall him. Barrett, who excelled in his first big league work, will be eligible to return Tuesday. Williams did not commit to any plan.

“We don’t know yet, depending on what happens the next few days,” Williams said. “But he’s doing fine. He’s competing. He’s doing all the things he needs to do. So we’ll see once Tuesday comes what happens there. For right now, X is here, and we need him.”

The Nationals will have another roster decision to make Saturday, so long as Denard Span completes his two-game rehab assignment Friday night at Class A Hagerstown without incident. The Nationals will presumably send Steven Souza Jr. back to Class AAA.

In the meantime, another reinforcement may be adding to his repertoire. Friday afternoon, around 3 p.m., infielder Zach Walters practiced catching fly balls and grounders in the outfield. Walters dismissed the practice as nothing significant. “I’m actually staying out of the infield so he has a nice infield,” Walters said, pointing to shortstop Ian Desmond.

Walters, though, has enough athleticism to play outfield, even if he’s played it just once before, in 2012, in 425 career minor league games. In four plate appearances, Walters has blasted two homers, including the go-ahead shot Wednesday in Miami.

“He was just messing around today” in the outfield, bench coach Randy Knorr said. “But if we need him, we’ll put him out there. He could do it.”