MIAMI -- The Nationals spent the days leading up to right-hander Tanner Roark's Friday night start trying to answer why the Marlins had hit Roark harder than any other team this season. Their coaching staff and Roark wondered whether he had been tipping his pitches.
Watching video confirmed what they had suspected, and while Roark did not want to get into specifics, he said he did notice certain tendencies on certain pitches. So he made an adjustment, and it paid off with a strong start to lead the Nationals to a 4-1 victory at Marlins Park.
Roark appeared to wiggle his glove more often -- with some exaggeration -- on the mound, perhaps an effort to disguise how he was gripping the ball for a certain pitch. He did keep the Marlins off-balanced, scattering six hits across 6 2/3 innings with seven strikeouts. Marcell Ozuna's solo homer in the fourth was his only mistake.
"I mixed it up a little bit, the game within the game," Roark said. "It was a little minor adjustment that I did, and it worked."
The Marlins had been a nemesis for Roark lately. Entering the game, he had lost each of his last five outings against them, dating back to last season. In his first three outings against Miami this season, Roark was 0-3 with an 8.40 ERA. Against the rest of the Majors, he is 2-0 with a 0.79 ERA.
Manager Dusty Baker worried that perhaps new Marlins hitting coach Barry Bonds picked up on something with Roark that gave their hitters an advantage. Baker recalled that Bonds was the best at spotting something in opposing pitchers.
But those issues did not trouble Roark on Friday.
"He was aggressive. He was coming right at them," Baker said. "He was getting strike one for the most part, and he was keeping them off-balance."
Jamal Collier covers the Nationals for MLB.com. Follow him on Twitter at @jamalcollier. This story was not subject to the approval of Major League Baseball or its clubs.