His check-engine light was illuminated, and his gas gauge was nearing empty, but James Paxton had little choice but to ignore those warning signs as July turned to August last summer.

The Boston Red Sox were 56-50 and 2½ games out of an American League wild-card spot when they opted to keep Paxton beyond the Aug. 1 trade deadline, a decision that came crashing down on both the team and the 35-year-old left-hander over the next five weeks.

Paxton, in his first full season since undergoing Tommy John surgery in 2021, did not make it to the finish line.

After going 6-2 with a 3.34 ERA in his first 13 starts, including a dominant June in which he went 3-0 with a 1.74 ERA in five games to earn AL pitcher of the month honors, Paxton went 1-3 with a 7.62 ERA in six starts from Aug. 4 to Sept. 1 and sat out the final month of the season because of an inflamed right knee.

The Red Sox crumbled in similar fashion, going 22-34 over the final two months of the season to finish 78-84 and 11 games out of playoff contention.

“It had been like 2½ years since I pitched [meaningful] innings in the big leagues, and I felt like I kind of reached a point where my body was just a little burned out,” said Paxton, who signed a one-year, $7-million deal with the Dodgers in late January. “I didn’t have much left in the tank.”

The Dodgers think the 6-foot-4, 212-pound Paxton, a Vancouver-area native who is nicknamed “The Big Maple,” has enough left in the tank to provide stability and a veteran presence to the back of a rebuilt rotation that appears strong and deep enough to make a World Series run.

“The upside is massive,” assistant pitching coach Connor McGuiness said. “I think it’s no secret that he’s got a little bit of injury history … but when he’s out there and healthy and doing his thing, I mean, he’s got some of the best stuff in baseball, especially when he’s running his fastball up to 96-97 miles per hour.”

Paxton missed the first six weeks of 2023 because of a right hamstring strain and the final month because of his knee issue, injuries that prompted the Dodgers to reduce the guaranteed amount of his contract from an originally agreed upon $11 million to $7 million with $4 million in incentives if he makes 18 starts.

Yet for a bulk of the time between those injuries, Paxton appeared to regain the form and fastball that helped him go 15-6 with a 3.82 ERA in 29 starts for the New York Yankees in 2019, his last full injury-free season.

Leaning mostly on a four-seamer that averaged 95.2 mph, an 81-mph curve and an 86-mph cut fastball, Paxton went 5-1 with a 3.00 ERA over nine starts in June and July, striking out 53 and walking 13 in 51 innings and yielding a .203 average and a .589 on-base-plus-slugging percentage.

But over his next six starts, Paxton yielded a .336 average and 1.065 OPS, struck out only 21 and walked 13 in 26 innings. He was tagged for nine homers in that stretch after giving up nine homers in 70 innings of his first 13 starts.

Paxton lost a little bit of steam on his fastball, which dipped to an average of 93.9 mph and 93.8 mph in two of his last six starts, and his breaking pitches lost some bite.

“The life on my stuff was not there,” Paxton said. “I could still throw hard, but I didn’t have any finish on anything. The ball was coming in kind of dead. And it doesn’t matter how hard you’re throwing, if it’s coming in dead, it’s sitting there on a tee for them. I felt kind of naked out there. I was grinding as hard as I could, and it just wasn’t coming.”

Another potential problem during his season-ending rough patch was that Paxton made his final three starts on regular four days’ rest. Paxton went 0-2 with a 9.39 ERA in four starts on four days’ rest last season and was 7-3 with a 3.57 ERA in 15 starts with five days’ or more of rest.

“Early in the season, I had a lot of extra rest, and then we went to a shorter leash,” Paxton said. “Coming off a surgery and that much time off, I wasn’t conditioned for that. If you start off going [every five days] your body gets accustomed to that, whereas if you go six all the time, that’s what your body gets accustomed to. We’re creatures of habit.”

The Dodgers won’t push Paxton like that. With the high-profile additions of Yoshinobu Yamamoto, who is transitioning from a once-a-week schedule in Japan, and Tyler Glasnow, who had Tommy John surgery in 2021 and hasn’t thrown more than 120 innings in any of his eight seasons, they plan to build in extra rest for their starters.

“It seems like when he gets that extra day, it really helps him,” McGuiness said of Paxton. “[The Red Sox] had to run him out there. They were in a pennant race, and he’s the type of guy who wants to go and help the team, so he’s not going to say no.

“But we have the luxury, given some of the guys we’ve signed, to run somewhat of a six-man rotation. So to get a guy of this caliber who’s looking to pitch in a six-man [rotation], you couldn’t ask for a better fit.”

The Dodgers, after poring over video from Paxton’s 2019 season, also plan to tweak Paxton’s mix of pitches, replacing his cutter with a “bullet” slider, which is thrown harder than a sweeper and has roughly equal parts horizontal and vertical movement.

“It’s a nice pitch to have because it works incredibly well to both sides of the plate, and it’s a more neutral pitch than a sweeper,” McGuiness said. “It helps him keep the ball down and underneath the swing of a right-handed hitter and down and away from a left-handed hitter.”

Paxton made his exhibition debut against the Cincinnati Reds on Thursday night, giving up two hits and a run in the first inning and striking out the side — Christian Encarnacion-Strand and Mike Ford with fastballs, and Stuart Fairchild with an 83-mph curve — in the second.

“I felt like I was able to find my velocity with the fastball last year, and that was big for me, but I’m looking forward to using the breaking stuff more this year — I feel like I’m in a better spot with it,” Paxton said. “And I’ll be ready to throw more innings this year. The body feels really good, so I’m ready to go.”