Ryan Zimmerman. (Photo by Jonathan Newton / The Washington Post)

On Stephen Strasburg’s checklist for areas of improvement this spring was improving his ability to hold runners on base. He has tried to in the past, but he often and understandably turns his focus entirely to the batter at the plate and away from the runner. Over the past four-plus weeks, Strasburg has made a concerted effort to vary his times in between pitches to throw off the runner’s timing and step off the rubber to force the runner back to the base.

Strasburg allowed the leadoff runner to reach in the first three innings of Saturday’s 2-1 win over the Miami Marlins in Jupiter, Fla., so he had several opportunities to put his improvements to work. Strasburg was deliberate pitching from the stretch against the Marlins and managed to hold all three baserunners in place. Over his four innings, the right-hander allowed only two hits, walked one batter, struck out four and fired 62 pitches, 42 of them for strikes.

Holding runners on is becoming second nature for him. “It’s definitely getting a lot better,” Strasburg said.

“He’s got a routine he’s thinking about so he’s letting the ball go and throwing strikes,” Manager Matt Williams said. “The indicator there is if he’s not throwing strikes or he’s out of rhythm. But I don’t see it.”

Strasburg allowed leadoff single to Rafael Furcal in the first inning. Even though Furcal is nursing a sore hamstring, he took leads off first base and Strasburg stepped off a handful of times. Strasburg induced two lineouts and a groundout to escape the inning. After allowing a leadoff walk in the second, Strasburg struck out two and got another flyout.

Josh Rodriguez singled to lead off the third inning, but Strasburg held him on to keep the double-play possibility alive. Furcal hit a grounder to Adam LaRoche in the next at-bat and he threw Rodriguez out at second. Strasburg then struck out the remaining batters of the inning. Strasburg’s control was perhaps the best of his three spring starts.

“I felt good,” he said. “Went out there and was able to build off of last start. I was able to work on things and get the pitches a little bit tighter.”

>>> Saturday’s pitching matchup was a marquee one: Strasburg vs. Jose Fernandez, the 2013 NL Rookie of the Year. Fernandez struggled with control and the Nationals drew four walks and scored a run on two hits over his 4 1/3 innings. On Sunday in Viera, the Nationals will host the Detroit Tigers, a game that will feature another elite pitching matchup: right-handers Justin Verlander and Jordan Zimmermann.

>>> Ryan Zimmerman played for the first time in five days and went 0 for 3 with an RBI. He had been resting his sore right shoulder, which he attributes to the heavy workload of grounders and throwing this spring. After Saturday’s game in which he was the designated hitter, he said he felt good. Williams said Zimmerman is tentatively scheduled to play third base on Sunday, but that hinges on how he feels after taking grounders in the morning.

While Zimmerman didn’t play in the past four games, he threw on Friday and before Saturday’s game. “The point of taking those days off was to get rid of it now instead of having to deal with it during the season,” he said. “It’s the smart thing to do and if I feel better we’ll be back in there.”

Zimmerman could always stay in the lineup as a designated hitter if his shoulder needs more time to rest. But he said: “I don’t need too many at-bats. It feels fine when I hit and has felt fine the past couple days throwing.”

>>> Wilson Ramos continued his torrid hitting this spring. He went 1 for 4 with an RBI on Saturday, and now is hitting .385 (10 for 26) with a team-high 11 RBI.

>>> Tyler Clippard, Jerry Blevins and Aaron Barrett each fired scoreless innings and looked impressive. Clippard looked, perhaps, the best of the bunch on Saturday and has yet to allow a run in five innings this spring. Barrett also hasn’t give up a run over eight innings and has struck out seven and walked none. Blevins struck out two on Saturday and his command has looked good over his six spring outings.