Duke determined to improve on recent struggles

WASHINGTON -- Nationals reliever Zach Duke endured his second consecutive rough outing on Saturday, continuing what has been a trying season. The left-hander, filling a long-relief role, has not worked frequently, but when he has, he often has struggled.

"I'm not commanding the ball, working behind in the count, and then throwing the ball down the middle," Duke said. "That's what it all boils down to."

The 30-year-old has tossed 15 innings over nine appearances, surrendering 22 hits and compiling an 8.40 ERA. On Saturday, he gave up four runs in two-thirds of an inning.

That appearance came nearly two weeks after Duke's previous one, when he gave up three runs in three innings on April 30 at Atlanta. He admitted that the infrequent work is a factor, but he said it's something he has to overcome.

"It's tough. I haven't done this role before, but at the same time I'm a professional and I should be better than that," Duke said. "I expect more of myself. I can't do that to this team."

The Nationals signed Duke to a one-year, $700,000 Major League deal this offseason after he made eight solid relief appearances for the club last September. The former Pirates starter had gone 15-5 with a 3.51 ERA in 26 starts for Triple-A Syracuse before his recall.

But Duke -- the only lefty in the Nationals' bullpen -- has struggled to get going since his season debut, when the Reds reached him for six runs -- five earned -- in 2 2/3 innings on April 5. Now he's working on drills to try to find a consistent rhythm and release point, as well as stay sharp between outings.

"I'm realistic," Duke said. "I know this game's all about results, and I'm prepared to do the work to get better results."

Andrew Simon is a reporter for MLB.com. Follow him on Twitter @HitTheCutoff. This story was not subject to the approval of Major League Baseball or its clubs.