Sammy Solis has struggled to find his way this season. (John McDonnell/The Washington Post)

PHILADELPHIA — Little by little, the Washington Nationals’ bullpen has stabilized since the team sold off its veterans and watched others lose time to injury. Sean Doolittle is back. Greg Holland found his old closing form. Koda Glover, moved out of the closer’s role and into a set-up spot, has provided nine straight scoreless appearances. Beyond them, Wander Suero, Jimmy Cordero, Austen Williams and others have shown promise in unexpected duty, auditioning for their future long before this team was supposed to be able to hold auditions at all.

But as other relievers have emerged and the bullpen has reorganized around unexpected stalwarts, Sammy Solis has all but disappeared. Before Wednesday’s series finale against the Phillies, the lefty played catch in left field with his fellow Nationals relievers, a brief session for all of them, given their heavy workload Tuesday night. When they dispersed, Solis walked up to a group that included pitching coach Derek Lilliquist, bullpen coach Henry Blanco and bullpen catcher Nilson Robledo, and he began mimicking his release point, as if he had noticed something and wanted their opinions. A few seconds later, he retreated to throw a few pitches, then walked back to demonstrate his release point again.

Even in the least significant moments of a reliever’s day, Solis is wondering, working and hoping. Because even as this team has been desperate for relief during this crazy stretch of schedule, Solis has appeared just once in the past week.

“Obviously the season has taken a turn I didn’t really see coming. I’m just rolling with it,” said Solis, who is pitching to a 10.24 ERA over his past 13 big league outings dating to late July. “I’m doing what I can. The phone doesn’t ring for my name as much as it did, and that’s the way it goes sometimes. You got to pitch better if you want to be in high-leverage situations.”

Entering the season, the Nationals thought Solis would be their left-handed answer in those high-leverage situations. Outside of Doolittle, whose left-handedness is irrelevant to matchups in his closer role, the Nationals saw Solis as their top left-handed option — a versatile type who could eat innings or match his explosive fastball against the best a lefty opponent had to offer. They thought so highly of him that Solis was the one on the mound when the go-ahead runs scored in Game 5 of both the 2016 and 2017 National League Division Series. Their second-round pick in the 2010 draft, that is, the guy they took after Bryce Harper, was always a big part of the Nationals’ plans, first as a starter and more recently as a reliever.

But this season, his last with options, has altered his status within the organization. That he is pitching to a 5.97 ERA over 53 games is problematic, but a few bad outings can expand a reliever’s ERA beyond recognition. The bigger problem, the one Manager Dave Martinez cited when the Nationals sent Solis to Class AAA Syracuse for the second time this season, is he is struggling to retire left-handers — the very hitters this team desperately needs him to handle. Lefties have an .897 OPS against Solis this season, righties a .738 mark.

Martinez also has cited problems with Solis’s execution, and others who have watched him agree. Fastballs that are supposed to be up slide a half-foot too low, and powerful left-handed hitters punish them. Solis falls behind, then forces himself to execute perfectly, and doesn’t always do so. But execution, like so many things in baseball, is easier to point to than to rectify.

“I’ve been working with all the guys as far as, what do you guys see when I go out there as far as pitch selection, mechanics, mentality, approach to these hitters. There are so many things it could be,” Solis said. “I feel like I’ve made some good pitches that have gotten hit. That’s just the way the game goes. But maybe sometimes you’re tipping a pitch. Other times you’re repeating a sequence they’ve picked up on. A lot of work is going into this thing.”

Solis feels urgency in the process. This offseason is the first in which he will be arbitration-eligible, so his salary will depend on his performance, which has not been as good as he hoped this season. Beyond that, next season is his first without minor league options. In other words, if he does not make the major league roster, the Nationals will have to place him on waivers, and if another team claims him, he will have to leave the only organization he has ever known. The 30-year-old’s career is at a pivot point, and he knows it.

“I’m not worried per se, but the season is kind of coming to a close here,” Solis said. “I just want to end it right and on the right foot with the organization and my teammates and see what happens in the offseason.”

The last few weeks of this season will likely influence the way the Nationals rebuild their bullpen this offseason, particularly in regards to left-handers. Outside of Doolittle, whom the Nationals acquired to close, not to be a matchup lefty, they have not prioritized elite left-handers much in recent years, banking on the growth of Solis and others. Matt Grace has emerged as a reliable option, capable of both eating innings and matching up late. He will be under team control next season, though he is also out of options and does not have the traditional strikeout stuff most teams look for in their late-game lefty. Tim Collins will be a free agent, though the Nationals could choose to pursue him for depth next year as they did when they signed him for this season.

In the meantime, a strong finish from Solis might encourage the Nationals about his place on the team moving forward. A slow finish could leave him with a great deal to prove a few months from now, when his career might reach a crossroads many in the organization did not expect it would reach.

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