If the Nationals make the playoffs, does Tanner Roark start or come out of the bullpen? (Matt Slocum/Associated Press)

Around 3:15 p.m. Tuesday inside Citizens Bank Park, Tanner Roark jogged between rows of blue seats, up and down cement stairs. He dripped with sweat when he finished and walked into the Nationals clubhouse.

“I’m a big believer in hard work pays off,” Roark said, taking a swig of orange Gatorade. “Luck rolls on your side when you work hard.”

The residue of Roark’s work this season has led to, in the words of his manager, “unchartered territory.” In a hard-luck loss to the Phillies Monday night, Roark reached 166 2/3 innings for his first full season in the majors. The total surpassed his previous high for a professional season, the 159 1/3 innings he threw last season between the minors and majors.

Roark has been one of the Nationals’ most valuable pitchers, perhaps the most valuable. He leads the staff with 4.4 wins above replacement, according to Baseball-Reference.com. He is tied for the team lead with 12 wins. His 2.81 ERA ranks second on the rotation, as do his innings.

Roark’s place in a potential Nationals playoff rotation, though, remains a topic worthy of discussion. Roark has had a much better season than Gio Gonzalez. But Gonzalez is one of the league’s most accomplished left-handers over the past five seasons. It is not a decision Manager Matt Williams needs to make now, and the next month may decide for him. Most likely, it will be difficult.

After he finished his workout Tuesday, Roark was asked: if the Nationals make the playoffs, would it matter to him if he pitched in the rotation or out of the bullpen?

“We will make the playoffs,” Roark said. “And I’d love to stay a starter. But there’s other factors that come into play. If I come out of the bullpen, I’ve done that last year, anyway. I’m comfortable with it. I would prefer to stay starting. But I’ll roll with the punches.”

Roark’s status may depend in part on how he maintains stamina through the season’s final month. Williams said the Nationals have already started to monitor Roark’s workload.

“It’s important for us to keep an eye on that,” Williams said. “It’s unchartered territory. We are in the business of winning games, and we’re going to continue to give him the ball and have him pitch for us, because he’s been really, really good. But we have to keep an eye on where he gets to and how many innings he gets to, kind of monitor that the next five weeks. He’s pitched so many innings because he’s been so good. That’s a good thing. But we have to keep an eye on it, too.”

Just to be clear: this is not an innings-limit situation. Roark has never suffered a serious arm injury. At 27, his arm is fully developed.

“Tanner’s not a power pitcher, per se,” Williams said. “Lack of velocity on any given start makes his ball move even more. I look at his command and say that’s important. We don’t want to get him in a situation where he throws too many innings and hurts his arm. He feels strong. He looks fine. We’ll just have to see how it goes.”

Williams said the Nationals have not considered skipping Roark in the rotation. But within a game, Williams could pull Roark early to keep him fresh.

“If we have a good lead and he’s through seven, we may not send him out for the eighth,” Williams said. “Not necessarily skipping, but being mindful of where he’s at, innings-wise, pitch-count-wise. If those situations arise, look at potentially getting him out of a game if we’re ahead. Those are the decisions you have to make in situations like this, where you’ve got a young pitcher that hasn’t been here before. We’ll continue to monitor that.”

Roark has shown no signs of wear.  His ERA since the all-star break is 2.70, compared to 2.91 before it. In his past two starts, Roark has thrown seven scoreless innings and allowed two runs in six innings despite a 33-pitch first inning. His average fastball velocity this season is 91.1 miles per hour. In his past six starts, his fastball has averaged between 90.8 and 92 mph.

Pitching coach Steve McCatty said he has kept a close eye on Roark as he moved past his previous career high in innings. He focuses on how Roark keeps pitches down and the depth of break to Roark’s curveball. So far, McCatty has seen nothing amiss. McCatty gives every starter the option to throw less in their between-start bullpen session. Roark has yet to ask for it.

“With Tanner, I feel comfortable the way he’s throwing the ball,” McCatty said. “He’s older. He did it last year. He’s doing it now. I do watch for things. But he hasn’t shown me anything that shows he’s getting tired.

“We always keep an eye out. I’m not real concerned about it. I don’t foresee skipping anybody or any extra days or anything like that. It’s not the time to do it. It’s time to go to the whip, man. That’s what it is.”

Roark said he feels healthy and strong, the product of his workout routine. He has not made special concessions or done extra work to keep in shape for the a full year in the majors. He has only struck to his usual routine, and he doesn’t take days off.

“Work hard,” Roark said. “That’s my motto, I guess. Don’t slack. Just keep working hard – running, working out, keeping in shape, not just eating everything in sight. I haven’t even had a cheesesteak yet. And I want one so bad.”