Doug Fister in spring training. (Photo by John McDonnell/The Washington Post)

As he nears his expected return to the majors, Doug Fister made the first of two anticipated minor league rehab starts on Sunday with Class A Potomac. He threw 59 pitches, 42 for strikes, over four innings. He struck out three batters, walked none and allowed six hits. The right-handed starter allowed three unearned runs — thanks to two errors and a passed ball by the defense — but was pleased with how he felt after he left the game.

“I felt really good,” Fister said. “I felt strong. I felt like I was going back out there for another couple innings. That’s a definite positive for me, mentally and physically. A step in the right direction and looking forward to the next one.”

Fister plans to make his next rehab start Friday at Class AA Harrisburg, where he may work with starting catcher Wilson Ramos as Ramos rehabs a broken hamate bone. If all goes well, Fister could make his Nationals debut five days later.

Fister, the Nationals‘ prized offseason acquisition, recovered from early-spring elbow inflammation in time for the regular season, only to suffer a lat strain late in spring training. He has been on the disabled list all season. He made two starts in extended spring training before his Sunday rehab start. His lat muscle is no longer an issue.

“No discomfort,” he said. “No anything. Felt loose where I needed it to be.”

Fister was rusty in his first inning on Sunday against the Lynchburg Hillcats, the Atlanta Braves’ Class A affiliate. His command wasn’t completely sharp; he threw 26 pitches, 18 for strikes. He gave up two hits, one a hard-hit single to left. His defense made two mistakes — an error and passed ball — and two unearned runs scored. For the second out, Fister induced a comebacker but threw to first base, instead of trying to start a double play.

“First inning felt a little rusty,” he said. “I needed to get my baseball sense about me and make a couple stupid plays. It’s one of those things that’s kinda slow out of the gate. But to finish feeling the way I did was certainly a positive.”

Fister cruised through much of the next three innings. He needed only 15 pitches to get through the second and third innings. The sinkerball pitcher allowed a hit in the second inning but, in his typical manner, erased it with a double play. He allowed three hits in the fourth inning, although two of them would likely have been outs in the majors leagues. He focused on location and the feel of his pitches in the latter innings, especially his off-speed ones.

“I still need to work on the cutter,” he said. “That’s something that comes along at the end but I needed to make sure the other three were solid.”

Fister’s fastball sat between 86 and 88 mph, even hitting 89 mph a few times, according to scouts’ radar guns. Last season with Detroit, Fister’s fastball averaged 88.6 mph.

“Stuff felt good,” he said. “Normally for me that’s a spring training velocity. I’m not a big velocity guy. I don’t pay much attention to it. During rehab kind of things, you take it with a grain of salt. It’s another check mark you have to make. For me, that’s an okay velocity. It’ll take that to this point.”

The initial plan for Fister was that he would make a second rehab start, aiming for five innings and 75 pitches in that game before rejoining the Nationals. With that timetable, he could ready to return around May 7. After he how he felt Sunday, Fister said that’s still possible.

“But there are always hiccups and certain things you have to make sure to take care of,” he said. “We’re going to take care of this (Monday) and see how we go. I’m not sure what the future holds for me but right now I feel good and I’m gonna go meet with the team now.”