PHILADELPHIA — Just after 4 p.m. on Wednesday, Jeremy Hellickson ducked away from a beating afternoon sun and into the visitors’ clubhouse at Citizens Bank Park. Sweat dripped off the pitcher’s chin and onto the carpet. Hellickson then encountered Washington Nationals Manager Dave Martinez in a narrow hallway, and a big smile spread across Martinez’s face.

“Feeling good, Helly?” Martinez asked, his arms stretched out as if he were about to go in for a hug.

Hellickson, always calm, nodded yes before heading toward his locker. He had just finished throwing his first bullpen session since Aug. 18, when he went on the disabled list with a right wrist sprain. He threw 30 total pitches, but he was only able to toss fastballs and change-ups because throwing a curveball is still painful. Hellickson sprained his wrist when he stumbled while covering home plate Aug. 15 against the St. Louis Cardinals. His spot in the rotation has since been filled by Jefry Rodriguez — who notched the longest outing of his major league career when he threw six scoreless innings Sunday — but Hellickson is inching toward a September return.

The right-hander, 31, is 5-3 with a 3.57 ERA in 18 starts this season. He made a DL stint earlier this summer with a mild hamstring strain and had turned in spotty results after returning to the rotation. As for the next step in his rehabilitation, Hellickson will see how he feels Thursday morning and go from there.

“I’m pretty good about listening to my body and not trying to push it,” Hellickson said Wednesday. “But at the same time, there’s only a month left, so you want to try to get back out there as soon as you can.”

The Nationals might have a crowded rotation in the coming weeks, with both Hellickson and Joe Ross progressing toward the major league mound. Ross, who has missed all of this season while recovering from Tommy John surgery, is probably closer to returning. He threw six innings — his longest rehab start yet — for the Class AAA Syracuse Chiefs on Monday, and Martinez said recently that Ross could join the team once it expands its roster after this coming Monday. Whether Martinez uses Ross as a starter or reliever could largely depend on when Hellickson comes off the DL.

And there is also Rodriguez, who has made seven scattered starts across June, July and August this season and has a 2-1 record with a 4.54 ERA. Rodriguez has won two of his last three decisions and pitched five or more innings in each of his past four outings. Martinez repeatedly has expressed confidence in the 25-year-old but has not indicated whether he would choose him or Ross to fill out the starting rotation until Hellickson is ready.

Either way, Hellickson would be a welcome addition to the Nationals’ fleeting push back into the playoff picture. Hellickson has thrown his curveball 23.8 percent of the time this season, according to FanGraphs, which is the highest rate of his nine-year career. It is only the second time in his career that his curve makes up more than 20 percent of his total pitches. He will now have to throw it pain-free, or at least relatively so, before he gets any closer to a return.

“It feels good when I just kind of cast it, so I think it’s just trying to get the hard curveball down,” Hellickson said of the motion that is giving him trouble. “We’ll see how it feels [Thursday], if it’s achy or not.”

Read more on the Nationals