Red Sox Deadline Target: RHP Mitch Keller

May not be the sexiest starting pitcher in Pittsburgh, but right-hander Mitch Keller could make some sense for the Boston Red Sox this deadline season.

Photo Courtesy of Rayni Shiring via Getty Images

As a result of this recent 10-game winning streak, the Boston Red Sox have slingshot themselves to eight games over .500 and third place in the American League East.

In tandem with winning came continued success for right-handers Lucas Giolito and Brayan Bello, who’ve combined for a 2.45 earned run average across 92 innings pitched since the calendar flipped to June.

Thus begs the question: Does it change how Chief Baseball Officer Craig Breslow attacks adding pitching this deadline?

Obviously, adding the best pitcher available does the most to Boston’s rotational upside. However, being at the front-end of a contention window and an exciting young core already flashing tremendous potential, does it make sense for the team to push its chips in and really make a future-expensing move?

Previously, we discussed the possibility of Minnesota Twins right-hander Joe Ryan. However, to me, Ryan feels similar to left-hander Garrett Crochet, not necessarily in terms of talent, but in terms of smoke at the deadline but acquired in the offseason.

Red Sox Deadline Target: SP Joe Ryan

Perhaps an alternative, also having a tremendous 2025 season, is Pittsburgh Pirates right-hander Mitch Keller.

He isn’t unfamiliar to trade speculation. Before his extension, it felt like a foregone conclusion he wouldn’t survive his arbitration years in Pittsburgh. Funnily enough, now that he’s extended, it still feels like he won’t.

But, what’s there to like, not like, etc., about Keller?

What I like about Mitch Keller

Keller, 29, has a 3.48 ERA and 3.32 FIP in 119 innings pitched. Not only that, but the 28-year-old has three more years of team control at an average annual value of just over $18 million.

Getting a controllable asset is massive for a team looking to contend now and beyond. While the previously mentioned Ryan is also controlled beyond 2025, Keller is already extended through his age-32 season.

Through 2022, Keller was a pitcher of similar mold to Bello. Yes, he could get strikeouts but was most successful getting early contact and pitching deep into games.

This year, he’s just a tick below six innings per start, but he’s having a career-worst strikeout campaign yet preventing runs at a fantastic clip. A lot is made of a pitcher’s ability to get whiffs — I get it, it’s sexy — but routinely working into the sixth and seventh inning is also nice. Getting strikeouts helps, as it takes the defense out of the equation, but early contact helps keep pitch count down.

He’s also been an iron man as a big leaguer, making at least 31 appearances each of the past three seasons.

To get away with not racking up strikeouts in 2025, you have to manipulate contact. Despite not generating a ton of chase or whiffs, Keller misses the barrel and generates ground balls at an above average clip.

He also has an elite fastball in terms of run value and his sinker and sweeper both are above average offerings.

Is he a No. 2? No. But does he push someone like Bello down in the rotation and kick Tanner Houck and potentially Walker Buehler out of the rotation? Absolutely.

Here’s what a potential post-deadline rotation with Keller looks like:

1. LHP Garrett Crochet
2. RHP Lucas Giolito
3. RHP Mitch Keller
4. RHP Brayan Bello
5. RHPs Walker Buehler/Tanner Houck/Richard Fitts

What I don’t like

Keller has just one pitch with a whiff rate north of 25% and it’s his slider, which also gets hit. Across 93 plate appearances, his slider has a .314 average against with a .442 slug.

I also don't view Keller as someone who’d stand to gain much in a stuff bump should he be a postseason reliever. He’s a tried-and-true starter, and a good one, but he’s probably not going to magically become a whiff-getter in October.

Lastly, even if he maintains this kind of production deep into the season, how much of a needle-mover is he? He’s a very capable arm who lives in the strike zone, and perhaps beyond 2025 he becomes a more capable whiff-generator.

But they’d have to be *serious* believers in his arm talent to see that jump coming when he’s 30 years old and older.

What does the trade package look like?

Red Sox get: RHP Mitch Keller
Pirates get: IF Vaughn Grissom, OF Jhostynxon Garcia (No. 6 on Sox Prospects), IF Mikey Romero (No. 12) and cash considerations

Considering the season he’s having and team control beyond 2025, this trade package feels kind of light. However, Keller is already considered age-wise to be in the middle of his prime and not much of a dominant arm.

However, Pittsburgh gets total salary relief plus a fringe top 100 prospect in Garcia along with a former first-round pick in Romero. For the Red Sox, they are trading from multiple surpluses, as both prospects are blocked organizationally and no matter how well Grissom plays it appears there’s no real pathway back to Boston for him.

The Pirates have become a recurring trade partner for Breslow, whose made three trades with Pittsburgh. One was Nick Yorke for Quinn Priester, one was Chase Shugart to Matt McShane and one was Enmanuel Valdez for Joe Vogatsky.

This trade is more significant, but nice to negotiate with a person and organization you have a working relationship with.