(Matt Slocum/AP)

For all of Stephen Strasburg’s ability, there’s a painfully clear weakness to his game when he’s on the mound. Last season, he allowed 14 runners to steal bases, the most of any Nationals pitcher, who all generally struggle with it. (Last year, opponents stole 111 bases in 133 attempts on the Nationals, the second-worst percentage in the majors.) Opposing base stealers’ success rate against Strasburg — 88 percent — ranked in the top 10 in the majors. He admitted then it was an area to improve and, this spring, has been trying to attack that weakness.

Against the Atlanta Braves in a 7-2 loss on Monday, Strasburg was incredibly efficient and sharp over the first five innings. He started the game with two looking strikeouts of the first three batters. He induced easy groundouts and flyouts. He had innings of eight, nine and 11 pitches.

But when he came out for the sixth inning for the first time this spring, he allowed a single to pinch hitter Reed Johnson and then his delivery out of the stretch suffered. Strasburg was then facing the top of the Braves order and didn’t want Johnson to steal second with one out. His command wavered. He allowed another single, a walk and two runs on a single by Justin Upton.

“I changed the way I set up in the stretch and I’ve kind of got them in between what I was working on and what I’ve done in the past,” he said. “So it’s just about being comfortable out there and just getting the right feeling. I think early on I had the right feeling then it started to go away and I was missing more of my spots left and right and not throwing enough strikes.”

The best way to combat potential base stealers is to vary the time to the plate. Runners are thrown off and can’t predict a pitcher’s move home. Strasburg’s initial thought when a runner reaches base is to go back to his original delivery, concentrating mostly on the batter at the plate. When he tries to speed up his delivery home, however, he tries to speed up his arm, too, which causes him to elevate the ball. The lower and upper body are then not in sync.

“Or I try to play catch up with my arm and I usually throw it in the ground,” he said. “So it’s just a fine line. But I know when it’s feeling right, it’s there. It’s just trying to keep working on it and trust it out there.”

Said catcher Kurt Suzuki: “It just comes with time.” Added Manager Davey Johnson: “I hooked him when there was a chance to do it. But he’s been great all spring varying his times.”

Aside from the shaky sixth inning, Strasburg’s efficiency and endurance were encouraging. He tossed 76 pitches, 53 for strikes. (The breakdown was far better before the sixth inning.) He relied mostly on his fastball. His feel for his deadly change-up is in mid-season form. He is still getting a full grasp of throwing his curveball for strikes on both sides of the plate. The sinker, which is he trying to get to move less but with more purpose, are also progressing. Hitting the sixth inning was a welcome accomplishment.

“I think that’s what I’ve been trying to get through, getting through five and six with less pitches,” he said. “I was able to do that today and I know it’s only going to be a matter of time before it becomes more consistent and my mechanics aren’t going to break down as much as they did in the future.”

>>> Left-hander Zach Duke allowed two runs on three hits over 2/3 of an inning in relief of Strasburg. Johnson attributed that to a long layoff of six days, being too strong on throws and losing sink on pitches.

>>> Rafael Soriano was again spotless in his appearance, striking out one hitter and allowing no runs. He broke his rule of not facing division opponents during the spring.

>>> Tyler Clippard threw a perfect ninth inning and has been stellar this spring. He has thrown four scoreless appearances.

>>> Henry Rodriguez threw 2/3 of an inning and notched two quick outs before allowing a single and then hitting a batter. It was his second outing of the spring because of elbow surgery last season and Johnson said he yanked the right-hander because pitching coach Steve McCatty wants him on a low pitch count. Rodriguez will rest and then begin work on a regular schedule of throwing every other day.

>>> Almost-daily update: Bryce Harper is hitting .438/.455/.750 in 12 games.