WASHINGTON -- Sean Doolittle’s league-leading 48th game finished took him a step closer to freedom and the Nationals toward a problem.

Doolittle has a little-discussed clause in his contract: if he finishes 100 games from the start of 2018 through the end of 2019, what was a team contract option vests into a mutual option. Which means Doolittle is a mere 17 games finished from having a path to free agency after this season if he chose to opt-out. This would greatly complicate things for the Nationals. And he’s going to get there at this rate. Barely.

Monday’s close was rough. Doolittle allowed a first-pitch home run, a single, a double and another run, before finishing off the game and a 7-6 win. Priority one was achieved; the Nationals won. But, this marked two less-than-smooth ends in the last three outings. Everyone remembers the “debacle” -- Doolittle's word -- in New York on Friday. Monday will float away faster, though it raised his ERA to 3.73, led to a new career-high seventh home run allowed and continued to hack at his severely down year-over-year strikeout-to-walk rate.

It also marked Doolittle’s 52nd appearance this season. That’s the fourth-most of his career and a game back of tying for third-most in his major-league life. He hasn’t been in this space since 2014, back when Oakland pitched him relentlessly and shoulder problems soon followed. Doolittle made 61 appearances that year. He’ll crack that number easily this season at the rate he is going.

Which will also make his option narrowly vest. He has finished 40.7 percent of the Nationals’ games this season. Just 44 remain. If Doolittle works at the same rate down the stretch, that means he will finish 18 more games and 101 since 2018 -- giving him the option of free agency by a game.

Doolittle answered “yeah” when asked Monday by NBC Sports Washington if he knew what 100 games finished meant for his contractual future. Told he is on pace for that mark, Doolittle crossed his fingers (don’t read that as he wants to leave, read that as he wants to stay healthy to make it there for multiple reasons -- not the least of which is holding up for the team this year). He’s also grinding along to reach that point.

“I mean, that's five of seven (games pitched), in the middle of August ...” Doolittle said of his Monday outing. “I haven't put together a season like this in a while. I'm starting to feel it a little bit. These are the nights where you've got to dig deep and grind it out. Thank goodness we had a three-run lead.”

The team’s inability to expand leads is providing him little chance for rest. Since the All-Star break, 19 of the Nationals’ 29 games (65.6 percent) have been decided by three runs or less. Doolittle has appeared in 11 of the 19, as closers do.

The radar gun suggested Monday that Doolittle is fine. He hit 94 and even 95 mph during the ninth inning. Though, not all radar gun readings are alike. Was it an easy, explosive 94? A well-executed 94? Or a load-up 94 mph to get there on a night when trouble came early?

“I was loading up to get to 94 because I was trying to stay in an aggressive mindset after some adjustments I made after Friday’s debacle in New York,” Doolittle told NBC Sports Washington. “I was trying to really work on extension and keeping better direction toward home plate. Trying to stay in that aggressive mindset. I haven’t looked at it yet. [Monday], we won, so I’m going to decompress, [Tuesday] come in early, watch some film and look at some adjustments I can make so I can have a productive day [Tuesday].”

And when he mentions fatigue, where is that rooted?

“It’s an arm thing,” Doolittle told NBC Sports Washington. “Maybe a little bit back [too], you don’t have the same posture and you start recruiting a little bit, they see it a little bit better. I think I’ve had some of that the past couple games. But, if I can stay a little more compact and behind the ball, that’s when it really has that late life. You know…(sigh)...we won. I very rarely talk to you guys after we win. Normally it’s because I did something really cool.”

He was able to smile at that.

What’s more concerning is the recent run of homers against him. Four of the seven have come in the last two weeks. Doolittle tries to work a diagonal plane against a lot of hitters. Depending on the scouting report, down and in can work alongside up and away; the reverse can be true, too. Most of the homers he has allowed are coming on pitches down, but not in the locations he would want when pitching down. They’re mistakes born of him being too rotational and not direct enough to the plate.

“The [Josh] Donaldson fastball, that was the top of the zone,” Doolittle told NBC Sports Washington. “The others have been down. Haven’t had that life and that good ride and that’s where I get hurt. That’s not by design. I’m not trying to do that. I have to do a better job of my mechanics that will allow me to work better across the top there.”

He hopes to do it for at least 18 more games. That means the Nationals’ best closing option made it to the end of the season healthy, they often won late against division opponents and the postseason could well be next. It also means the offseason has a distinctly different look. Picking up a $6.5 million team option would be a no-brainer for a Nationals club which still needs a closer in 2020. Instead, if he continues a manic run in usage, Doolittle could well finish with a fresh voice in what’s next.

MORE NATIONALS NEWS: