Red Sox Prospect Outlook: Brandon Walter Among Boston’s Next Call-Ups?

Before the start of the 2023 season, NESN.com is evaluating several noteworthy prospects in the Boston Red Sox organization, using insight and analysis from industry experts to gauge each player’s outlook for the upcoming campaign. Next up: Brandon Walter.

The cancellation of the 2020 Minor League Baseball season due to the COVID-19 pandemic had wide-ranging ramifications, with some prospects suffering from the lack of game action while others used the time away to aid their development.

Brandon Walter falls into the latter camp, with 2021 being the season that really put him on the map. Now, he’s among the Red Sox’s top pitching prospects, with the potential to make a major-league impact sooner rather than later.

Here’s everything you need to know about Walter, an up-and-coming left-hander who could factor into Boston’s pitching plans as soon as 2023.

Walter’s story
Walter was a stud at the University of Delaware, but Tommy John surgery wiped out his entire 2018 season and cast uncertainty over his future. Still, the Red Sox took a flier on the lefty, nabbing him in the 26th round of the 2019 Major League Baseball Draft and signing him for $35,000, an investment that now looks like a bargain given Walter’s upward trajectory.

It took a little bit for Walter to find his footing in the Red Sox system, with the canceled 2020 MiLB season coming on the heels of a so-so professional debut in which he made just 13 relief appearances in rookie ball. His hard work during the pandemic was apparent when he returned to the mound in 2021, though, and his marked improvement opened the door for him to join the rotation, first at Single-A Salem and then at High-A Greenville.

Walter has been groomed as a starter ever since. And while he endured a setback in 2022, when he was limited to 11 starts due to a bulging disc in his upper back, he remains among the more intriguing arms in Boston’s farm system. Walter advanced to Triple-A Worcester last season after nine starts with Double-A Portland in which he posted a 2.88 ERA and a 0.78 WHIP with 68 strikeouts to just three walks across 50 innings pitched.

“Walter’s a fun one, because I think even the Red Sox didn’t realize what they had,” Ian Cundall, director of scouting for SoxProspects.com, recently told NESN.com. “The fact that in 2021 he was a reliever in Salem as a 24-year-old. And then he was so good, they moved him to the rotation, and then obviously last year in Double-A was just an insane performance to start the year.”

The Red Sox added Walter to their 40-man roster in November 2022, protecting him from the Rule 5 draft and perhaps signaling his big-league debut is imminent.

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Scouting report
Walter doesn’t blow away hitters with triple-digit heat. And he doesn’t need to. Because what the 26-year-old lacks in velocity — he sat around 89-92 mph with his fastball last season — he makes up for with a viable pitch mix and excellent strike-throwing capability.

Walter, listed at 6-foot-2, 200 pounds, also has a unique delivery, attacking hitters from a low, lefty arm slot that’s proven deceptive.

“He just really locates his fastball well, and he complements it with two potential above-average-to-plus secondary pitches,” Cundall said. “He’s got this really long, like, slurvy — kind of that typical sweepy breaking ball you see from that arm slot — with just a ton of horizontal movement. Really impressive pitch data behind it. And then he turns over his changeup really well.

“It’s one of those things where scouts go back and forth. Some think the breaking ball is better, some think the changeup is better. And it’s not because they’re both bad. It’s because they’re both good.”

Again, Walter’s fastball isn’t overpowering. So, he’s a rather uncommon prospect in an era where so many young hurlers light up the radar gun. But there still could be a little more gas than he flashed in 2022. He sat around 90-93 mph in 2021, while topping out around 95 mph.

“He used to show a little more velocity, but it kind of ticked down a little bit last year,” Cundall said. “He was still very successful. But he can really dot it. He has among the best command and control of the starting pitchers in the system.”

Overall, when it comes to Walter, the whole is better than the sum of his parts. It’s not the most electric profile, but it’s one that could play at the highest level, much to the Red Sox’s benefit.

“He has among the best command and control of the starting pitchers in the system.”

Ian Cundall, director of scouting for SoxProspects.com, on Brandon Walter

Most-likely outcome: Back-end, up-and-down starter.

The Red Sox theoretically could move Walter back to the bullpen — his role upon entering the system — if he fails to progress as a starter or Boston needs relief help down the road. But the overall profile points to a continued role in the rotation, with the level of success to be determined.

“100 percent, he’s going to be developed as a starter,” Cundall said. “Because in the bullpen, unlike guys like (Bryan) Mata, he just doesn’t have that explosive fastball that teams are kinda looking for in the bullpen. How many relievers are out there throwing 89, 90 to 92? Not that many anymore.

“Lefties, the bar is obviously different. There’s a different scale for lefties to righties. But I think especially with three pitches, and good command and control, that’s someone you develop as a starter.”

Health, and whether he’s able to maintain — or even build upon — the improved stuff he showed last season pre-injury, will go a long way toward determining Walter’s ceiling. That said, he appears to have a relatively high floor based on his current arsenal.

Best-case scenario: Mid-rotation starter.

Walter is a late bloomer, having traveled a circuitous path to potentially reaching the majors. As such, there’s been very little buzz about the crafty southpaw. It’ll be fascinating to see how the narrative changes if he makes good on his upside. The Red Sox just might have a rotation fixture on their hands.

“When you’ve got a three-pitch guy with good command, that’s the makings of a starting pitcher,” Cundall said. “Just the concerns to me are the fastball, making sure the fastball velocity comes back. Because, obviously, it played better at 91-93 (mph), 91-94 than it does at 88-91. So, let’s see if he can get back into the low 90s, because that obviously would be very encouraging. But when you have the polish he does, the three pitches, you can definitely dream on a starter.

“And I think there’s a chance that of all the Triple-A pitchers on the 40-man roster, or at least that we have projected right now — (Kutter) Crawford, (Josh) Winckowski, (Bryan) Mata, Walter, (Chris) Murphy — if I was to pick one who has the best chance to develop into a multiyear starter for the Red Sox, I think it would probably be him.”

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SoxProspects ranking: No. 8

Walter is the Red Sox’s second-ranked prospect, behind Bryan Mata, whom SoxProspects.com has listed at No. 6 in its overall rankings. It’s hard to imagine him climbing too much further, as he could graduate to the majors before that becomes a possibility.

Fenway forecast
Walter almost certainly will debut with Boston in 2023. Or 2024 at the very latest.

The Red Sox don’t have a need in their major-league rotation upon reporting to spring training, with Chris Sale, Corey Kluber, James Paxton, Nick Pivetta, Garrett Whitlock and Brayan Bello among those vying for five sports. And there are others on the organizational depth chart — including Crawford, Winckowski and maybe even Mata — who could earn earlier call-ups this season. But Walter’s time is coming, no doubt.