What is Zack Wheeler facing in his return from surgery? We asked two pitchers who have done it.

Seven months after surgery, Alex Cobb felt great. His arm was strong, his control spot on. He bounced back easily from long-tossing and throwing in the bullpen. He thought he was back.

Then, he pitched in a spring training game.

“I was throwing like 82 miles an hour,” Cobb recalled this week. “I thought that the [radar] gun was messed up.”

Now, this was 2012, before ballparks were equipped with technology to track the precise velocity and movement of each pitch. So, we’ll have to trust Cobb’s memory, which he concedes is “a bit foggy.”

But his points about returning to the mound after being treated for thoracic outlet syndrome were clear: It takes even longer than most pitchers think based on how they feel.

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And here’s the potentially good news for Zack Wheeler, the Phillies’ recovering ace: Velocity is often the last thing to come back, a detail offered up by Cobb without being asked about it specifically or told about how it relates to Wheeler.

“That was the biggest thing,” Cobb, who played in 13 seasons from 2011 to 2024, said by phone. “My velocity just, I couldn’t get it. I remember being pretty rattled about that. But at the same time, hitters were reacting the same to my pitches.”

Cobb is among the most successful examples of a major league pitcher returning from venous thoracic outlet syndrome, a condition that’s much less common than other pitching injuries. Like Wheeler, Cobb had his first rib removed to relieve the subclavian vein, which was compressed between the rib cage and collarbone.

Wheeler had surgery 6½ months ago. The 35-year-old righty is three starts into a minor league assignment that will continue Tuesday night for double-A Reading on the road in Somerset, N.J., and represents the last step before he rejoins the Phillies’ rotation. By all accounts, it’s going well.

One issue: His heater lacks its usual grade of octane.

Last season, Wheeler’s four-seam fastball averaged 96.1 mph, 20th among 139 starters who threw a minimum of 1,500 pitches. He threw 272 pitches at 97 mph or more, topping out at 98.8.

Through his start Wednesday night for triple-A Lehigh Valley, his fastball averaged 92.9 mph, which would rank 116th among 161 major league starters. He threw three pitches at 94 mph or more, topping out at 94.3.

OK, to be fair, Wheeler’s minor-league assignment is akin to his spring training. Two of his three starts were in sub-50-degree weather. He hasn’t felt the adrenaline rush of a major league game, which often produces a velocity spike.

It’s also not uncommon for Wheeler, even when healthy, to lack peak fastball velocity early in a season. In 2024, he averaged 93.1 mph and 93.9 in back-to-back early-April starts before dialing it up to 95.4 and 95.5 in his next two starts.

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And after 11 seasons in the majors, he no longer relies primarily on a blazing heater to get hitters out. He added a sweeper in 2023 and a splitter in ’24 to a preexisting curveball, cutter, and sinker, any of which can serve as outpitches depending on the day.

But pitching coach Caleb Cotham often describes the four-seamer as Wheeler’s “bread and butter.” It’s also his superpower. Last season, it produced a 30.5% swing-and-miss rate, tied for fourth among qualified starters.

With diminished velocity, Wheeler isn’t missing bats. He has thrown 54 four-seamers in triple A and gotten a total of one swing and miss. He threw 19 fastballs Wednesday night; nine were fouled off.

“I would like [the velocity] a little higher, obviously,“ Wheeler told reporters after allowing one run and striking out six (one on a fastball) in 4⅓ innings. “But it’s cold, still working my way back. Like we said, you’ve kind of got to be patient and don’t overdo it but maybe figure out some little things that can get you there.”

In separate conversations this week, Cobb and former major league starter Dillon Gee shared their experience with coming back from thoracic outlet syndrome and offered perspective on the challenges Wheeler is facing as he closes in on his return to the Phillies’ rotation.

On the eve of Wheeler’s major league debut for the Mets in July 2013, another New York pitcher allowed two runs in 8⅓ innings.

It was a post-surgery triumph for Gee.

Midway through the 2012 season, Gee developed a blood clot in the axillary artery in his throwing shoulder that was caused by thoracic outlet syndrome. Gee, then 26, got multiple opinions, including from St. Louis-based vascular surgeon Robert Thompson, who operated on him at the All-Star break.

Thompson also performed Wheeler’s surgery in September.

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“He was kind of one of the forerunners of figuring this stuff out,” Gee said by phone.

Gee recovered in time for a full spring training in 2013. He earned a spot in the Mets’ season-opening rotation and had a 3.62 ERA in 32 starts, the best year of his career. He was particularly effective later in the season, with a 2.74 ERA in the second half.

Physiologically, Gee said he didn’t detect a difference in pitching without his first rib, which he described as “a little bitty, tiny bone.” But he recalled taking longer than expected to pack on the pounds after surgery. Wheeler said he lost “a good bit” of weight and is still down about 10 pounds from his usual 205. The Phillies put him on a program to help gain it back.

“I do remember Thompson put you on this weird diet because it’s about some sort of lymphatic drainage stuff,” Gee said. “You can’t hardly even eat much of anything. It’s a weird diet. I definitely lost a lot of weight right after that surgery.”

Gee, who hasn’t spoken with Wheeler since his diagnosis last summer, speculated that the weight loss might be a factor in Wheeler’s velocity, which is down about 3 mph on all of his pitches, including the breaking balls.

It wasn’t as much of an issue for Gee because he never had a big fastball. Even before his first surgery, his heater averaged only 89.5 mph.

“My fastball,” Gee said, “was like his changeup.”

But Wheeler is also a more complete pitcher now than when Gee was around him early in his career. Although he added the sweeper and splitter within the last few years, he throws them frequently. The sweeper is a big swing-and-miss pitch; the splitter is a weapon against left-handed hitters.

“If he was a guy that just relied on his fastball, it’d be a lot more worrisome about being down 3 or 4 miles an hour,” Gee said. “Those [triple-A] starts alone are not really getting your competitive juices going very well. After he’s thrown quite a bit, he starts feeling more confident, and then you throw in [being] back in the big leagues and pitching for something, I could see it coming back. That’s just my opinion.

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“But even if, let’s say he doesn’t get back to full velocity — maybe if 96-97 is like 94-95, that’s still good, especially because his command just gets better and better. If you can command even low-90s to mid-90s and then have those other pitches, yeah, he’ll still be the same Wheeler.“

Gee had other blood clots later in his career caused by compression under the pectoralis minor muscle in his upper chest. He retired in 2018.

“There’s enough people that didn’t have a recurrence that I think you feel pretty comfortable about it,” Gee said. “It’s not a bad surgery to come back from, as long as they did everything they needed to do. And Wheels definitely has the odds in his favor just by being the [pitcher] that he was before.”

Nine starts into a promising rookie season with the Rays in 2011, Cobb felt like he was unable to loosen his arm. He pitched anyway. The next day, he was talking to roommate Brandon Gomes.

“I was like, ‘Hey man, does my arm look big to you?’” Cobb recalled. “And his eyes just got huge, and he’s like, ‘Dude, you need to go to the field right now.’”

A few days later, Cobb was in Dallas, undergoing surgery to relieve a compressed vein.

“Waking up out of surgery, I will always remember feeling like somebody took a shotgun to my collarbone,” said Cobb, who was 23 at the time. “I just woke up and flinched like I just got hit by something. It was pretty painful immediately after surgery. I’m glad I was as naive as I was because it’s kind of a pretty serious surgery.”

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But the return to competition, typically six to eight months, was straightforward, especially when compared with Tommy John surgery, which takes 10 to 12 months, or more. Cobb would know. He had both procedures, in addition to multiple knee and hip surgeries, during his career.

Cobb began the 2012 season on time in triple A and struggled with a 4.14 ERA through eight starts. The Rays called him up in May when an injury created a need in the rotation, and he pitched with diminished velocity for most of the first half of the season.

“I remember being extremely nervous, like more than my debut, just because I didn’t feel like I was polished the way I had been the year before,” Cobb said. “It definitely took me at least a full eight to 10 months [after surgery] to get my velocity. I probably got my velocity back in late July. So, maybe a full year actually.”

Cobb’s average fastball velocity slipped from 91.3 mph before surgery in 2011 to 90.2 upon his return in 2012. At times, though, he said he “dropped down to 85-86.” His fastball averaged 89.3 mph in two of his first three starts back in the majors, according to the data compiled at the time by Brooks Baseball.

Eventually, Cobb’s fastball velocity ticked back up to an average of 90.9 mph in 2013 and 91.5 in 2014. Based on experience, then, he believes Wheeler’s initial dip isn’t atypical.

“I would almost be encouraged with where he’s at,” Cobb said. “At this point, if he’s low 90s, in the minor leagues, cold [weather], coming off of thoracic, I think that’s very encouraging. In my case, the surgery did play a huge role in my velocity.

“Too early to tell, but I would say that it seems like the velocity does usually come back. If he’s already at that level and he’s got a good feel for all of his pitches — and just knowing that he’s one of the best in the game — I’d be optimistic.”