Max Scherzer is scheduled to face batters Tuesday. (Photo by Jonathan Newton/The Washington Post)

WEST PALM BEACH, Fla. — Max Scherzer emerged from his third bullpen of the spring Thursday unscathed and is scheduled to throw his first live batting practice session Tuesday, according to Nationals pitching coach Mike Maddux. Maddux, however, didn’t say if there was a target date for Scherzer to pitch in a game.

“We’re taking it a step at a time,” Maddux said.

Scherzer’s spring work has been delayed by a stress fracture in the bottom knuckle of his right ring finger, which forced him to withdraw from the World Baseball Classic. While he can throw his entire secondary pitch arsenal without pain, throwing his usual fastball generates discomfort, so he’s been using a three-fingered fastball. The 32-year-old Scherzer said the adjustment allowed him to build arm strength and he is prepared to use the unusual grip in games.

Maddux said he doesn’t know how different the three-fingered fastball is from Scherzer’s usual fastball, but he is comfortable with the reigning Cy Young Award winner using it in games.

“In watching him throw on the side, I feel much more comfortable than when he talked about it,” Maddux said. “After seeing it, I’m okay with it.”

Scherzer first experienced pain in the knuckle late last August, but pitched through it — expecting it to heal with rest after the season. But the discomfort persisted and an MRI exam revealed the stress fracture. A couple of weeks ago, he said he wasn’t sure if he’d be available for Opening Day, but the club has been encouraged by his progress.

“He was throwing the heck out the ball,” Nationals Manager Dusty Baker said. “I mean I had to ask him, ‘Was that a three-finger or were you using two?’ He said it was three. I never even dreamed of trying to throw with three fingers so you talk to anybody else out there I doubt they’ve ever tried it either.”

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Wilmer Difo is scheduled to come off the bench to play center field for one of the Nationals’ split squads against the Marlins in Jupiter Friday. Difo, who turns 25 next month, is a natural shortstop who has also played second and third base as a pro, but has never played the outfield. Instead, Difo’s experience is limited to taking fly balls in the outfield and working on throws, as he did Thursday in preparation for his debut.

“This is adding to his potential value,” Baker said. “We had hoped that Difo would play some outfield in the Dominican. It’s my understanding he didn’t play hardly at all out there, which is what we wanted. So we’ve got to do it here. We’re also experimenting with [Emmanuel] Burriss playing in the outfield, too. … Anytime you can move guys around and not lose anything defensively, that is a big, big, big plus.”

Difo and Burriss, an infielder who’s appeared in the outfield in seven games in his major league career, could presumably compete for the fourth outfield spot if their transitions go smoothly enough. Michael A. Taylor is seemingly the favorite, though Brian Goodwin is also a possibility.

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In addition to Stephen Strasburg, Ryan Zimmerman and Pedro Severino are scheduled to make their Grapefruit League debuts Friday. Both will start. Zimmerman will play first base and bat sixth. Severino, whose debut was delayed by shoulder soreness, will catch and bat seventh.

Matt Wieters, on the other hand, is still a few days away from his spring debut, according to Baker. The catcher officially signed with the Nationals on Feb. 24.

“He’s getting over some soreness just from training and not being here,” Baker said. “I don’t care how you train by yourself. When you train by yourself, or away from here, your training is probably no more than a couple hours, probably, max. It usually doesn’t take that long to work out. But when you’re out here, now you’re out here all day. You’re not squatting, catching people all day. You’re not throwing quite as much. You’re not running. The main thing is, you’re not on your feet all day long. You see how long we’re out here. I mean, some of it is sitting down. But until the games start, you’re on your foot most of the morning.”