Free agency is just in its infancy, but there are tickles up and down the spectrum already. One of the more interesting tidbits surrounding a player not at the top of The Athletic’s ranking of free agents was that teams are interested in Phillies reliever Jeff Hoffman as a starter. This conversion might seem more surprising if we didn’t just have eight players perform that feat in 2024 — with two of them doing so while changing teams in free agency — but it’s also something that is attempted more often than it’s pulled off.
Relievers usually end up relieving because of a host of reasons, including command, health, arsenal breadth and fastball quality. If a starting pitcher lacks some combination of these things, they can expect a conversation about changing their role on the pitching staff. A successful starter generally needs to have a passable fastball, be healthy enough, have the ability to command a couple of pitches, and have a pitch or two that works against lefties and righties.
If there’s a rule of thumb for why starters become relievers, we should be able to establish some sort of roadmap back. What are the characteristics of relievers who have successfully converted to starting? Does Hoffman show those characteristics? Which other relievers could follow the same path?
In 2021, two pitchers converted from relieving to starting. Since then, every season has seen at least seven pitchers put up 15 starts the year after they started fewer than a third of their games. No matter how well they pitched, they gave their new teams an average of 131 innings — a boon to any organization. This gives us a decent sample of 26 successful conversions in the Hawk-Eye era.
The pitchers who converted to starting:
- Lost stuff (of course) to the tune of 8 points of Stuff+
- Lost fastball stuff (12 points of Stuff+)
- Averaged two pitches they could command (> 100 Location+)
That’s pretty much all they shared as a group. They’re evenly split in terms of four-seamers and two-seamers as their primary fastball. Fewer than half had great changeups, so that’s not a requirement for the plan. Traditionally, we’ve thought of arsenal size as well, but we’ve had plenty of conversions in the past few years who did so despite throwing just two or three pitches regularly — think of Justin Steele, Cristian Javier, Garrett Crochet and Freddy Peralta, perhaps.
Most of the pitchers had enough stuff to be able to lose stuff and be competitive by those pitching models, whether you judge their stuff by their full arsenal, or by their fastball alone. Almost all of the conversions could command at least one pitch well, and most could command two or more well. The pitchers that had sinkers as their primary fastball did have more pitches and good command of those pitches — guys like Clarke Schmidt, Ranger Suarez, Michael King, Zack Littell, Trevor Williams and Michael Lorenzen fit that bill.
So that’s what we are looking for. If we limit last year’s set of relievers to just those who could afford losing all that stuff off their arsenal and their fastball, have located two or more pitches well, and have a wide arsenal if their best fastball is a sinker, we get a list of 20 pitchers who fit the bill. With an eye for health outcomes — sorry Mason Miller and Hunter Harvey — we can shorten that list a bit to produce our possible converters:
|
Name
|
Stuff+
|
Stf+ FA
|
Loc+ Pitches
|
Sinker%
|
|---|---|---|---|---|
 Emmanuel Clase |
146
|
206
|
4
|
0%
|
 Tanner Scott |
145
|
151
|
2
|
0%
|
 Jeremiah Estrada |
142
|
161
|
2
|
0%
|
 Robert Suarez |
137
|
143
|
3
|
15%
|
 Griffin Jax |
134
|
115
|
5
|
10%
|
 Nate Pearson |
128
|
126
|
3
|
2%
|
 Orion Kerkering |
128
|
114
|
2
|
15%
|
 A.J. Puk |
123
|
139
|
3
|
15%
|
|
121
|
130
|
2
|
0%
|
|
 Evan Phillips |
121
|
114
|
2
|
10%
|
 Victor Vodnik |
120
|
120
|
2
|
0%
|
 Adrian Morejon |
120
|
123
|
3
|
36%
|
 Mike Baumann |
119
|
125
|
2
|
0%
|
|
Jeff Hoffman |
116
|
118
|
3
|
8%
|
 Keegan Akin |
112
|
111
|
3
|
0%
|
 Beau Brieske |
110
|
120
|
2
|
16%
|
Look! There’s Hoffman. You’ll also see A.J. Puk, who tried converting last year, and Keegan Akin, who has oscillated back and forth between the bullpen and the rotation. Despite the fact that Emmanuel Clase will probably never start again, this list feels pretty good for its purposes. Let’s highlight six pitchers on and off this list for further exploration.
Jeff Hoffman, free agent
The former Phillies reliever locates both of his fastballs well and has enough stuff to handle the loss that would come with longer outings, theoretically at least. So why didn’t it work for him as a starter the first time? His environments have to take some of the blame. Pitching in Colorado is not only terrible for your ERA, but it also can affect your ability to stay healthy, given what altitude does for recovery. Then he tried starting in Cincinnati, perhaps the second most difficult place to pitch in the big leagues. Finally, his arsenal has really changed over the years, from a dead zone fastball with a slower curveball and a changeup he never had confidence in to a riding four-seamer, hard gyro slider (which is fairly platoon neutral), and a splitter he has been able to locate well over the last two seasons. This new arsenal should work against both hands, should his body hold up to the new role.
Griffin Jax, Twins
Jax was also a starter once, back in 2021, and it didn’t go swimmingly. His ERA was over six and he gave up two and a half homers per nine innings. But, like Hoffman, things were different then. Jax averaged 92.6 mph on the fastball, not 97.1 mph, and his fastball had three inches less ride back then. He had the sweeper, but it was 5 mph slower in 2021. He’s added a sinker, changed the curveball to more of a power curve, and finally pushed his changeup grade over the average by focusing more on the velocity than the shape. Jax now has two fastballs, two breaking balls and a useable changeup in his bag, and he locates all of them really well. He admitted this year that he’s open to starting, so the question is only how many ticks he’ll lose off the fastball if he has to pitch deeper into games. One spring could sort that out pretty quickly.
Nate Pearson, Cubs
Once Pearson ended up on the Cubs after the deadline, more than half of his appearances were longer than one inning, and none were on a back-to-back. That might be significant for a couple of reasons. For one, Pearson has struggled enough with health to think he shouldn’t be on this list. But maybe a stricter schedule with more rest will be the ticket to keeping him healthy. On top of that, it also stands to reason that the Cubs are keeping the door open for Pearson to start. Pearson isn’t known for his command, but he’s located his slider well at times, and he located his new sinker well enough to think that might give him a fastball he can spot. He only threw one splitter last year, but it showed promise, and some who have worked with him think it can be a real asset. Even without it, he’s got two elite breaking balls and enough stuff to handle the transition.
Adrian Morejon, Padres
Here’s another one where the health may not allow the conversation to really progress. Morejon threw over 72 innings combined in 2024, and that’s the high-water mark for his career. But he’s also been between the ‘pen and the rotation for most of his career, so maybe a more defined role could help him stay on the bump. He’s also a sinker-first lefty, which isn’t great for platoon splits. But he has stuff in spades, and his four-seamer is a decent pitch with surprisingly enough ride to work. He added a splitter last year that batters hit .105 against and now has two breaking balls in the sweeper and the harder gyro slider. He’s had some up-and-down walk rates, but his underlying locations — especially on the fastball and slider — have almost always been above average. His team could use him in the rotation, but if the Padres add a starter, they could also use a power lefty in the bullpen after they lost Tanner Scott. He’ll probably stay in the bullpen.
Beau Brieske, Tigers
It’s possible Brieske is neither a starter nor a reliever. His game log this year oscillated from outings of three innings to ones where he was just asked to get two outs. That continued into the postseason, where he was electric in both roles. With two fastballs, a slider and a changeup, he doesn’t have platoon worries, and his locations and walk rates have been mostly fine since he got to the big leagues. It is worth pointing out that when he was starting in 2022, he sat at 94 mph instead of 96 and his fastball Stuff+ was nearly thirty points lower — maybe he just doesn’t have the fastball to start. That said, he’s added some ride since then, so maybe a better shape will keep him just above break-even on the fastball as a starter. There’s probably more of a need in the ‘pen in Detroit, so maybe that’s the direction he’s headed, but it is possible he could be successful in either role.
Michael Kopech, Dodgers
He’s not officially on this list because he doesn’t command the ball well, but he’s admitted that he’s still open to starting, and there might be some energy for that in his organization. He’s in this sample in a different way — as a successful reliever-to-starter convert from his 2022-2023 seasons. Kopech obviously has the stuff to handle the conversion, and it’s possible that his new cutter is a better lefty-neutralizer than the changeup he was using in 2022. Yes, the command is a problem, but he could just slot into the part of the list featuring Javier, Crochet, Tanner Houck and Jose Soriano. Those four did not succeed because of any command they’d previously shown. Instead, they used lethal pitches and just enough touch to make it work. The guess is that Kopech stays in the bullpen, though.
(Top photo: Hunter Martin / Getty Images)
