Fernando Abad (Jonathan Newton/TWP)

The jumbled roles of the Nationals‘ bullpen has eaten at Manager Davey Johnson all season, and more so now. Nearly a fourth of the way through the season, he has yet to find a comfortable routine with the bullpen. Other than a few exceptions, he still doesn’t have a defined roles for every reliever. Injuries and early pitching inconsistency have wrecked havoc on the bullpen, and Johnson feels responsible for not having a full handle on it.

“That keeps me up actually even more than the offense because I actually feel the offense is going to come around,” he said. “But how I use the bullpen against the opposing team’s lineup and bench, I haven’t got to a comfort zone there yet and I think it’s affecting productivity.”

Part of the issue, however, may have been the lack of a second left-handed reliever as well as limited use of Henry Rodriguez. Until Saturday, Johnson hadn’t shown full confidence in the reliever, who he has slowly eased back offseason elbow surgery.

For much of the season, Johnson had essentially been operating with a six-man bullpen, using Rodriguez almost only in losses. But if Johnson wants to help restore order to the bullpen, using Rodriguez more often could help. On Saturday, Rodriguez entered a 3-3 ballgame in the seventh, the first time he’d entered a game with the Nationals tied or ahead in a month and a half, and fired 99- and 100-mph fastballs during a scoreless inning.

Another potential part of the solution to the topsy-turvy bullpen arrived this week, when Ryan Mattheus landed on the disabled list with a broken hand and the Nationals called up Fernando Abad, a left-hander they have been impressed with since he was signed to a minor league deal from the Houston Astros this offseason.

“Not having the configuration I had last year it made it a little harder for me to separate and get the kinda balance you want on both sides of my bullpen,” Johnson said. “So I’m still mixing and matching and trying to get it. That’s my biggest concern going forward to keep everybody fresh.”

Last season, Johnson had the luxury of three left-handers, with sinker-baller Sean Burnett available to face hitters from both sides of the plate. Entering the season, Johnson envisioned using right-hander Craig Stammen and left-hander Zach Duke as the dual long relievers. He paired right-handers Mattheus and Rodriguez together, perhaps as seventh-inning relievers, with sinker-baller Stammen as a security blanket for hairy situations. He saw right-handers Tyler Clippard and Drew Storen as eighth-inning setup men, with Clippard facing the left-handed batters. Closer Rafael Soriano’s role was clear.

The Nationals, however, haven’t been able to stick to that script. Early starting-pitching inconsistency had its ripple effects on the bullpen. Storen’s command troubles and Rodriguez being used in specific situations also have hampered the bullpen. The Nationals believed their right-handers were capable of getting left-handed batters out but Mattheus had only one strong season against left-handers, in 2011; this season, left-handers were hitting .452 against him.

As Johnson continues to work through the bullpen roles, Abad, 27, could be a prime candidate to fill Mattheus’s role. At Class AAA Syracuse, Abad punched up a 1.06 ERA over 17 innings, striking out 12 and walking only two. He served as a setup man, pitching the seventh or eighth innings, facing both left and right-handed batters. He throws his change-up to neutralize right-handers and his sinker and slider combination to left-handers.

On Saturday, Johnson called on Abad to make his Nationals debut and pitch the ninth of a 5-3 game. He fired a 96-mph fastballs to left-hander Ben Revere, the hardest he’s thrown in his career. He threw sinkers to Humberto Quintero and walked him but struck out Jimmy Rollins on a 94-mph fastball and induced a pop out from Freddy Galvis with a fastball.

Abad struggled with the Astros last season, posting a 5.09 ERA in 46 innings. He attributed his inconsistent season to arm fatigue. He was a late inning reliever, then started and the toll of winter ball wore on him. He rested this offseason and built up his endurance.

“I think it’s because I’m throwing the ball harder this year and locating better,” Abad said. “Last year, I didn’t have as much control because my arm didn’t feel as good. I was tired because I’d thrown during the winter. I’ve got more strength and I’m more effective than before.”

Abad has been with the Nationals less than a week but he could provide Johnson with an arm that could help bring some balance to the bullpen.

“Any time the manager gives me an opportunity I’ll do what I know what to do and it doesn’t matter what happens,” Abad said. “They know what they’ll do. I’m not focused on who is hurt. I’m focused on doing my job … I don’t think he has the trust in me yet. I’ll win that by my job here. And I’m ready for whatever inning he needs me for.”