Stephen Strasburg delivers. (Photo by Katherine Frey/The Washington Post)

VIERA, Fla. — In his fourth start of the spring season, Stephen Strasburg was at his best. Even though he took the mound against the Yankees’ cross-state traveling squad, Strasburg spun five scoreless innings, allowed six hits, walked none and pitched out of jams. He needed only 68 pitches and notched nine strikeouts.

“It’s progress,” Strasburg said after the 13-0 win over the Yankees. “My change-up was a lot better [Wednesday]. I feel like I was finishing the pitch better and not yanking it as many times. The curveball felt good. Fastball command, yeah, always gonna work on that.”

But Strasburg undersold how dominating his change-up was Wednesday. In fact, he was underselling his entire performance — but more on that later. Strasburg has said he wants to improve that change-up this spring and learn to throw it to a different spot over the plate. He victimized a few Yankees with the pitch, which appeared to have sharper but less overall movement to the untrained eye.

“It’s easy for them to spit on it when it’s yanked out of the hand,” Strasburg said. “It’s not a pitch that’s competitive so I throw it hard and let it work.”

Manager Dusty Baker had another way of describing the pitch: “Boy, his change-up was electric.”

Baker said catcher Wilson Ramos directed Strasburg well through his five innings of work, particularly during one jam in which he loaded the bases with no outs. Baker said the bench was hoping for the strikeout followed by a double play, which capped a scoreless third inning. Even then, Baker noticed Strasburg wasn’t happy or emotional.

“He threw the ball well and he still came off the field shaking his head like he didn’t throw the ball well,” Baker said. “So I’m learning about Stras. Is he ever really happy? Well, we’re trying to make him happier. Just appreciate when you have a good outing, because there’s plenty of bad ones coming. And who knows, this might be the year when he doesn’t have any?”

>>> Baker was pleased with the Nationals’ offense against the Yankees, who started Masahiro Tanaka — the Nationals shelled him for seven runs on nine hits over four innings. The third inning provided the Nationals’ best effort: Ben Revere singled, Anthony Rendon singled, Bryce Harper walked, Ryan Zimmerman grounded out but drove in a run, Jayson Werth singled (and was later thrown out at home), Chris Heisey doubled, Wilson Ramos homered and then Brendan Ryan grounded out to end the frame.

“It appears that off day came right on time,” Baker said. “Our legs seemed fresh. We seemed quicker, rejuvenated. Especially the guys that started the game. Anthony Rendon, that’s the best I’ve seen him so far this year.”

>>> Baker is giving players staggered, unscheduled days off. “When I think you’re looking good and might be close to ready, see you tomorrow,” he said.

Players don’t have to come to the stadium during their days off. They can stay at home to rest, pack up their belongings for the trip back to D.C., spend time with the family or lounge at the beach. Werth was gone the other day. Revere gets one Thursday.

“That’s what [Tommy] Lasorda used to do for us,” Baker said.

>>> Danny Espinosa won’t play at home at Space Coast Stadium because, according to Baker, he has trouble seeing the ball thanks to the batter’s eye. Baker said Espinosa, who is 3 for 25 this spring, will play road games and minor league games at home with Class AA and AAA players.

>>> Baker said Shawn Kelley, who has recently only pitched on the minor league side, is doing so simply to build up his workload. “Kelley is pretty much kind of a lock here but we just gotta get him straight and get his innings in, and having the other guys come here so we can see ‘em and see ‘em against competition,” Baker said.

In recent appearances, Kelley was clocked by scouts at 89-91 mph. His fastball averaged 91.9 mph last season with the Padres. He has allowed three runs in 4 1/3 big league spring training innings, striking out one and walking one.