The first thing you’ll probably notice about RJ Petit is his size— he’s 6-foot, 8-inches tall. Generally speaking, the Colorado Rockies are not a height-challenged team, but even then, Petit towers above his teammates. It’s fitting, then, that his size reflects the notable changes he’s undergone over the course of the last year as he found himself on a different team, underwent Tommy John surgery, and changed his look.
It’s all part of the process for Petit as he moves into the next stage of his career as a professional baseball player.
The 26-year-old righty talked with Tread Athletics about his early days as a baseball player in Rock Hill, South Carolina.
“I was playing baseball at 3 with my dad flipping balls for me to hit,” he said.
Eventually, however, he turned to pitching after “enjoying it more than hitting.”
Entering his senior year of high school in 2018, Petit knew he wanted to play college ball, but that seemed unlikely given that this fastball maxed out at 83-85 mph. So he started a velo program to address the issue and saw results. That summer he committed to playing for Charleston Southern.
After spending two years with the Buccaneers, in 2021, things began to come together. That year, Petit’s fastball was in the mid-90s, and he had a 2.79 ERA in 84.0 IP. He was also selected to the Big South Baseball First Team All-Conference.
(The Buccaneers website suggests that’s the same year Petit’s signature mustache made its debut.)
In 2021, he was drafted by the Detroit Tigers in the 14th round of the MLB Draft, and he began making his way through their minor league system. Petit earned a 3.40 ERA over five minor-league seasons in 243.1 IP. He was especially good in 2025 when he spent time in Double-A and Triple-A while posting a 2.44 ERA in 66.1 IP that included two starts. His fastball was up to 98 mph while his changeup and slider were working. In addition to having a 10.72 K/9 in Triple-A, Petit also boasted a 51.0 GB%.
However, he was left unprotected in the 2025 Rule 5 Draft, and that’s where the Rockies entered the picture.
For a rebuilding Rockies team that had recently hired former Detroit Tigers pitching coach Gabe Ribas, claiming Petit seemed a logical move.
As for Petit, he assumed that he would not get through the Rule 5 Draft. He just didn’t know where his next stop would be.
“It was a big change,” he said. “It’s been a whirlwind, changing orgs, but it’s been awesome so far.”
Taking a spring training detour
Petit was moving through spring training with the Rockies, where he had 4.0 IP and a 6.75 ERA, when things began to tilt, starting — as it often does with pitchers — with some arm pain.
“It was weird,” Petit said. “I’ve dealt with arm pain before, just soreness and always thinking you can get through it, or throw through it, never really thinking the worst. And then one outing, it just didn’t really feel good, and I was like, ‘I’m just sore’ because I felt a little bit better the next day.”
His optimism was short-lived
“It was an outing against Team USA where I was warming up, and I was like, ‘Okay, something’s wrong,’ but I was still naive — ‘Oh, it’s not that wrong.’ And then still went out there.”
The pain reached a level for Petit where he was no longer focused on pitching.
“I was kind of just in my own head, kind of screaming, ‘What’s going on?’ because every throw, it just felt terrible.”
As it turned out, Petit would require Tommy John surgery to repair his elbow. Accepting the news was difficult.
“It was, in a way, world crashing down all at once,” he said. “I know baseball isn’t everything, but it is a massive part of my life. So it wasn’t easy to hear. I was really emotional at that point in time, but I think I also did a really good job of moving past the feeling-sorry-for-myself stage.
“When I found out, (the coaches) were like, ‘Yeah, just go home. Take the day’ because it was pretty early.”
So Petit did some hard thinking.
“And honestly, on that drive home, I was just thinking about everything. Didn’t play any music. [I] was just thinking, just going back and forth. But I realized how blessed I am, and that this whole journey and plan that’s laid out for me, I have no control of, and God has great things waiting for me. And this is just part of it, and it’s only going to, in the long run, make me stronger, physically, mentally. And (I’m) blessed to have the organization behind me, their support constantly, great surgeons, awesome PTs every single day. So I’m not just left out in the dark. I’m in a really good spot.”
As it turns out, Petit was not done with surprises.
First, consider some basic human anatomy. When a pitcher’s ulnar collateral ligament (UCL) is replaced in his elbow, surgeons prefer to transfer part of the palmaris longus tendon from the forearm/inner wrist. However many people do not have one, and, for all his size, Petit doesn’t either. So the surgeon instead took part of Petit’s hamstring that connects near his left knee.
But he didn’t know that when the procedure began.
“Coming out of surgery, I was fully expecting everything that was going on with the elbow,” Petit said. “I didn’t expect the knee to hurt so bad because that’s where they took a graft from.”
It’s led to a more complex rehab that he expected.
“So far, my elbow stinks, but I expected it to. But the knee and the hamstring have been way more annoying because I can’t move around as easy.”
Petit noted that he’s feeling better now, but in the meantime, he’s going through the tedium of rehab. During the Rockies last homestand, he was wearing a hinged elbow brace that limits the range of motion for his right arm. Every Friday, however, the PT changes the settings, and he gains a little more mobility, occasions he thinks of as “one-week anniversaries.”
His surgery took place on a Friday, so Fridays have become progress markers.
“Okay, this week you get your bandages off,” Petit explained. “We’re going to cut the stitches this week. You can take a shower. I was like, ‘Oh my gosh, thank you. Thank you, Lord’ because that wasn’t easy.”
The first two weeks were especially tough. He was not allowed to sweat in order to avoid infection.
But after two weeks, he was allowed to shower and begin lifting.
“And I was like, ‘Oh my gosh, I feel a little bit normal again.’”
Lucas Gilbreath, a Tommy John recipient himself, told me once that the biggest misunderstanding about the Tommy John is the tedium of recovery.
“It’s the same every day,” he said.
“We start rehab at 8:00, and then it’s about 3 (hours) and 45 minutes of just passive range-of-motion stuff, where I’m literally just laying on the table,” he said.
“Then I’m just moving through it and getting to see where I can get, and me being like, ‘Oh, that feels bad today,’ or, ‘Oh no, it feels really good today.’ And just working through it, seeing what we got. And then from there, we just have a bunch of exercises that we do, and slowly building up weight, slowly building up reps and sets, and then gaining new exercises that test it a little bit more and just go through more movements.”
In the meantime, there’s just boredom.
“I’ve accepted it,” Petit said, “I’ll drag my feet around, and I’ll still get out of there at 11:30. I’ll go for a nice 30-minute walk on one of the fields out at the facility. That’s not even on my program. That’s just to get outside and move a little bit.”
But he knows it’s part of the process.
Plus, he’s part of a supportive community.
“Obviously, it sucks. A lot of guys have had it, but I think that also helps seeing guys in the locker room that have had it before, and they’re fine. They’re good now.”
That said, it’s still hard.
“The rehab is just what it is. You’ll get through that fine,” Petit said. “It’s just stay positive. Stay with it. Make sure you talk to your good people around you. Stay grounded. Stay mentally sane. Don’t let the boringness and the monotonousness of the rehab take over because that’ll be what really gets you.”
An obvious question for any pitcher recovering from Tommy John would be if they attempted to throw from their non-pitching hand.
“I did try and throw left handed,” he said. “It was really bad.”
The switch would have been challenging for any pitcher, but it was made impossible by the missing ligament in his leg.
“When I tried to throw lefty, I strained my hamstring again, or felt my hamstring because I forgot that you push off of that leg,” he said. “So I tried to throw one left-handed as a joke when we were walking on the agility field because there was just the ball sitting out there. So I picked it up and threw it with my left hand, and it made my hamstring hurt. So I was like, ‘Okay, probably gonna stay away from that.’”
A joke in the Rockies spring training clubhouse was the Petit and fellow reliever Zach Agnos were big and little versions of each other with their distinctive dark hair and mustaches — and very different heights. (Agnos stands six feet tall.)
That’s no longer the case.
While Agnos continues as he always has with this Rollie Fingers-esque mustache, Petit would almost be unrecognizable if not for his size given that he has cut his hair and shaved.
It was a move he saw as inevitable.
“I did that three days before I got surgery,” he said, “because I brushed my hair. I took good care of it. I brushed my hair every morning, and it was already a pain in the butt to wash and condition and then dry. And I was like, ‘Man, that’s probably gonna be pretty tough with one arm for a little while.’ So I was like, ‘You know what? It’s just new time in my life. Let’s just reset everything.’ And then the mustache just came off with it.”
Can fans expect to see Petit’s look return? He’s not sure.
“The hair, that’ll probably take a little while.”
He’d just gotten a fade four days earlier, so he’d be starting from scratch.
“I do like the flow . . . .”
The mustache, however, is an entirely different matter.
“The mustache, I can have the mustache back in a month. So I think I’ll time it up. One of the times I come back up here throughout the year, I’ll have the ‘stache.”
As for Rockies fans, they can expect to see Petit back on the field — with or without the mustache — next year.
This week on the internet
In case you missed Mickey Moniak and Troy Johnston on the MLB Network last week, here you go.
Kyle Freeland will be back in the Rockies rotation tonight. Bill Lasden talked with Freeland about his recovery in addition to what’s different in the Rockies clubhouse this season.
Charlie Wright asks the key question.
The Rockies are tied with the Minnesota Twins for the highest success rate (55%). It’s more positive news for the rebuilding Rockies.
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