VIERA, Fla. -- John Baker knew he'd be tested, and he welcomed the challenge.
Baker, making his first spring training start at catcher after missing time with a nagging right forearm strain, threw out two runners trying to advance in the Marlins' 5-3 victory over the Washington Nationals on Saturday.
"They're in our division. They know I haven't been catching," Baker said. "I expected them to go and I'm glad they did, because it was a good test for me."
Baker double-clutched on a Roger Bernadina stolen base in the first, then nabbed Cristian Guzman trying to swipe second after a one-out single in the third inning. Ryan Zimmerman followed with a single but was caught at second when he tried to move up after a pitch from starter Chris Volstad skittered away from Baker's block.
"Arm strength feels good," said Baker, who had been relegated to pinch hitting and designated hitter duty. "I know I had a good time on the second throw, when Guzman tried to steal second. It's not so much about how hard I throw for me; it's about what my time is and getting rid of the ball."
Baker was 2 for 2 with a walk and helped settle down right-hander Volstad, who rebounded from a shaky start to work five effective innings behind a hard-to-hit sinker. Volstad walked two and struck out two.
Volstad allowed a run on six hits -- four of them coming on grounders- and made an adjustment on his sinker after Zimmerman's RBI double put the Nationals ahead 1-0 in the first. On Baker's advice, Volstad made sure his money pitch ran over the lower portion of the plate, daring Washington hitters to take a hack.
"I counted 11 groundballs," Marlins manager Fredi Gonzalez said. "With a sinkerballer, that's what you want."
Once Volstad gained confidence in his sinker, he didn't shy away from the pitch, Baker said.
"It was great. It was something we could go to. We never got off of it, even though he had trouble throwing strikes in the first inning," Baker said.
Cameron Maybin hit two solo homers and Gaby Sanchez added a two-run shot for Florida. Maybin is rounding into form after missing time with a left groin injury and Sanchez is trying to win the Marlins' first base job.
"(Maybin) smoked a couple of those balls. Those balls were against the wind," Gonzalez said. "That's what you see from him, and that's a good sign. It's only his second game back after sitting 11, so his timing's pretty good."
Guzman, the Nationals' shortstop, has been playing the field only sporadically while recovering from offseason surgery to fix a shoulder problem that plagued him last season.
He finally had to test himself on a ball in the hole when Donnie Murphy shot a grounder to his right in the second inning, but Guzman threw high and wide of first base and was charged with an error.
"We're going to get to a point pretty soon where we'll have to test it more thoroughly, just see how he's going to respond," Washington manager Jim Riggleman said.
Riggleman thinks Guzman is battling a mental block when it comes to unleashing a throw from the hole. The Nationals have Ian Desmond, who is hitting .343 with a team-high 12 RBI this spring, as a backup plan at short.
"When (Guzman) gets over that hurdle in his mind and realizes he can throw it over there without having a problem, then we'll see him do it," Riggleman said. "Right now, he must be a little tentative because he didn't let that ball go."
Right-hander Garrett Mock allowed three runs on six hits over five innings, the longest outing by a Nationals starter this spring. He walked one and stuck out four.
Tim Wood worked the ninth for a save. ... Before the game, the Nationals optioned their top pitching prospect, RHP Stephen Strasburg, to Double-A Harrisburg and optioned LHP Matt Chico to Triple-A Syracuse. LHP Doug Slaten, RHP Drew Storen and C Jamie Burke was reassigned to the minor league camp, leaving Washington with 39 players in major league camp.