Red Sox Free Agent Targets: Jack Flaherty and the Need for More Reliable Arms

Despite trade rumors and interest in top-of-the-rotation arms, the Boston Red Sox should be extremely interested in adding Jack Flaherty no matter who else suits up for Boston in the starting rotation next year. I know all the knocks against Flaherty, I’m from near St. Louis and I watched his struggles with the Cardinals. I know how the Cardinals fans STILL talk trash about him, especially after his success in Detroit and Los Angeles this season. What stands out to me is how easily Flaherty has put his time in STL behind him and grown as a baseball player. If the rumors are true, adding someone of Flaherty’s status makes a lot of sense for the Red Sox, but there are also some reasons to possibly look elsewhere.

Let’s start with the pros. This season Flaherty made 28 starts, going 13-7 with 15 quality starts. He posted a 3.17 ERA, 1.07 WHIP, and a 10.78 K/9. Flaherty ran an excellent 32% whiff rate, something else that was sorely lacking in Boston’s starting rotation this season. Flaherty is a fastball-first pitcher, and he backs that fastball up with a solid slider and an excellent knuckle curve with a nasty break. Flaherty doesn't throw very hard at this point in his career, but there’s enough of a speed differential between all three pitches that they can play well off one another. 

Flaherty's spray chart shows very clearly the biggest potential downside of bringing him to Boston. When you overlay all of his balls in play on top of Fenway Park, you can see that pitching half of his games there might not be in his best interest. A lot of gray outs and purple doubles suddenly turn into home runs when you change stadiums. There’s reason to believe that when the Red Sox front office and coaching staff look at this kind of information, they’ll have be discouraged from giving Flaherty more than a second thought during discussions.

On top of the possible issues with the long ball at home games, Flaherty presents some injury risk in the rotation. He spent time on the injured list in 2024 with both the Tigers and the Dodgers and has a history of right shoulder issues. On top of that, a trade with the Yankees was nixed at the last minute because of concerns about his medicals. The Dodgers obviously thought that the medicals weren’t an issue and although he spent some time on the shelf with them, they were largely rewarded for the gamble. If Boston's medical staff feels strongly that Flaherty runs little risk of reaggravation or believes they can work with him to strengthen his shoulder, then this will be far less of a concern.

The Athletic projects Flaherty to sign a 3-year, $68-million contract this offseason, and if the Red Sox are truly opening the pocketbook and bringing in big-name free agents, they could do a lot worse than Flaherty. He knows the AL East well from his stint with the Orioles and has proven that he can be trusted throughout October. While his spray chart may not line up well with the home ballpark, that kind of track record should make him desirable to a Red Sox team that needs not just a frontline starter, but a veteran who can provide reliable innings and show up in high-pressure starts.