PHILADELPHIA -- It was a month ago that Patrick Corbin's rocky 2022 season bottomed out in a disastrous performance at Citizens Bank Park.

The Nationals' left-hander allowed six runs on five hits, two walks and a hit batsman in just two-thirds of an inning on Aug. 6. Corbin allowed as many home runs as he recorded outs while his season ERA soared to 7.02. It was after that start that the Nats elected to skip Corbin's next turn in the rotation to give him a chance to reset.

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It had seemed to do the trick. Corbin entered Friday night having posted a 2.96 ERA in his four starts since returning to the rotation, including a 1.96 ERA in his last three outings.

In his return trip to Philadelphia, however, Corbin flashed some of the same struggles that have plagued him for the better part of the past two seasons. This outing was much longer than his last one against the Phils -- he battled through 6 2/3 innings -- but the result was more of the same.

Corbin allowed five runs and a season-high-tying 12 hits while taking his 18th loss of the season in the Nationals' 5-3 defeat to open the three-game series at Citizens Bank Park on Friday night. He pounded the strike zone early and often -- throwing 54 of his 69 pitches for strikes -- but the Phillies frequently pounced on those offerings.

"That last one, I didn't get out of the first [inning], but I had a little break, and like I said, I've been feeling pretty good," Corbin said. "They're a good lineup there. They're trying to get hits, I'm trying to get them out, and tonight, it just didn't happen."

Corbin allowed 15 hard-hit balls (exit velocity of at least 95 mph, per Statcast), including 10 with an exit velocity of at least 100 mph. He's allowed 139 batted balls of at least 100 mph this season, the most by any pitcher in the Majors. That number jumps to 278 dating to the start of last season -- also the most by any pitcher.

While the exit velocity was certainly an issue, there was an encouraging sign when it came to Corbin's pitch velocity. His sinker averaged 93.5 mph (up from his season average of 92.9) and it topped out at 95.4 mph. He also maintained that velocity deep into his outing, with five of his six fastest pitches coming in the sixth inning.

The problem, however, was Corbin threw that pitch on 54 of his 69 offerings (78%). He worked in 13 sliders and two four-seamers.

"What I'd like to see him do more, especially the third time through the order, is throw his changeup," manager Dave Martinez said. "They had all those righties in there, so I thought it'd be the perfect spot to throw his changeup -- and he didn't throw any. That's something we'll talk to him about the next day or two."

For his part, Corbin said he isn't opposed to using it more -- the opportunity just didn’t present itself this time around.

"It wasn't my plan to just throw a bunch of fastballs tonight, it just kind of seemed to go that way," Corbin said. "Obviously, I'd love to do that -- tonight was just a different game. I'd definitely love to throw changeups, throw sliders. Mix it up and see what happens."

As it stands now, Corbin likely has three more starts this season. Though he's just two losses shy of becoming the first pitcher to lose 20 games since 2003 (Detroit's Mike Maroth) -- and the first NL pitcher to do so since 1979 (Atlanta's Phil Niekro) -- Corbin has no plans to pack it in early.

"I couldn't care less about that. I try to win every day," Corbin said. "I'll go out there and take the ball no matter what. Just go out there and compete."

If Corbin indeed stays on turn down the stretch, the focus will be more on preparing for 2023 than trying to salvage any ‘22 numbers.

With the 33-year-old southpaw under contract through the ‘24 season, Martinez knows that a strong finish could go a long way toward helping Corbin rediscover the form that made him a two-time All-Star with the D-backs and saw him garner a share of NL Cy Young votes in his debut season with the Nationals in 2019.

"It's very important for him and for us, as well," Martinez said. "He's a big part of what we're going to do here in the future. I know he's a veteran guy, but we need starting pitching."