(Nick Wass/AP)

While several of the Nationals’ offseason moves have come under question through an underwhelming ten weeks of baseball — the Michael Morse trade, the Dan Haren signing, only one left-hander in the bullpen — one small move this winter has been, so far, a resounding and unheralded success: the signing of 27-year-old Fernando Abad. Since his call-up from Class AAA Syracuse in late May, Abad has logged 10 straight scoreless appearances and helped restore some order to a recently jumbled bullpen.

On Tuesday, he entered in the eighth inning against the heart of the Rockies lineup. He allowed a leadoff single to right-handed Nolan Arenado, who fouled off four of Abad’s pitches in a tough at-bat. But then Abad sat down left-handed slugger Carlos Gonzalez on four pitches, firing low 92 and 94 mile per hour fastball and burying a curveball low and away for the strike out.

Abad did the same to right-handed Troy Tulowitzki and left-handed Todd Helton, attacking them with fastballs on the edges of the strike zone and finishing both of them with curveballs. His pairing of a 93 to 95 mph fastballs and a curveball have proved a deadly combination. After his final strikeout, Abad raced off the mound and pointed to the sky, the left-hander’s emphatic way of celebrating his string of success.

“He looked great,” Manager Davey Johnson said. “He had the meat of the lineup. He’s a big addition. Trying to keep from overusing him.”

Johnson’s statement speaks volumes of his budding trust in Abad. In just over two weeks, he has already turned to Abad 10 times, six of them for at least a complete inning. The Nationals signed Abad to a minor league deal this offseason after he parted ways with the Houston Astros this winter. He attributed his struggles with the Astros to arm fatigue and spend this offseason working out more and not pitching in winter league baseball. He arrived in camp as a extreme long shot in a crowded bullpen but by the end of camp had drawn the attention of all in the organization. When injuries beset the Nationals pitching staff, he was the first reliever called up from the minors.

As Johnson begins to establish order to the bullpen, Abad adds a needed element. In addition to Tyler Clippard, who is successful against left-handed batters, and recent left-handed call-up Ian Krol, Johnson has three options against left-handed heavy opponents. Before, when Zach Duke struggled as a long man and against left-handers, Johnson could only safely turn to Clippard in crucial spots. Albeit a small sample size, Abad has held right-handers to a .105 average and left-handers to a .200 average.

>>> The Nationals made official the roster moves expected for Wednesday’s game: they selected the contract of Ross Ohlendorf from Class AAA Syracuse and, to make room on the active roster, optioned Nate Karns to Class AA Harrisburg.

But to make room on the 40-man roster, Christian Garcia, who has been on the disabled list since the start of the season, to the 60-day disabled list. It was a procedural, roster-juggling move as Garcia is still rehabbing at Syracuse. He made his second appearance for Syracuse on Tuesday night, a scoreless inning, since moving up from Harrisburg. The clock on his rehab assignment runs out at the end of this month and could be an option for the bullpen soon.