Former first rounder Gavin Williams had a breakout season in 2025, finishing the year with a 3.06 ERA and 25% strikeout rate. He is currently slated to fill a top of the rotation slot this season. The question is not whether Williams is good, but rather if his process is sustainable enough for ace-level success. So we are going to dig in and explore: What does Gavin Williams look like as the ace of the Guardians rotation?
Background:
Williams’ 3.06 ERA is that of a top of the rotation starter, but his 4.39 FIP and 4.30 xERA tell a different story. These gaps of over 1 run each indicate that Williams outperformed expectation. His FIP and xERA are both more in line with stats of a mid-rotation starter.
Based on this, can Williams continue to limit runs at the level he did, or were his results in 2025 due in part to favorable outcomes?
To figure that out, let’s establish some key characteristics of a rotation’s ace:
- Above average control and consistently gets ahead in the count.
- Can face both hands. Has pitches that can put away hitters.
- Typically has a strong fastball.
- Underlying metrics that support a clear method for getting outs (through high miss, ground balls, etc).
Williams does show potential for these traits, but not yet consistently.
What Can Williams Improve?
There are two major steps Williams can take to show improvement:
- Better results against his fourseam
- Throwing in-zone more
Results Against the Fourseam
Williams’ fourseam has below average results vs both hands. He tried to mitigate this issue in 2025 by adding a sweeper vs righties and increasing his curveball usage vs lefties. Both his sweeper and his curveball get stronger results in terms of generating ground balls, chase, and in-zone miss.
But even with this usage change, the results against the fourseam were still worse than average. This is not because of the pitch shape alone. The results can also be attributed to location and count leverage.
One way he can improve the results against his fourseam is to throw it in zone more consistently. The fourseam gets below average chase, but average in-zone miss. So, he is better off trying to throw it to his spots in zone as much as possible. The issue is that Williams has below average control and command overall.
If we look at his heatmap for fourseams in 2025, it seems like Williams had a strong idea where he needed to throw (upper and outer halves vs both hands):
But due to his below average control, many fourseams ended up as non-competitive out of zone.
He can also start improving his count leverage and throw his fourseam in specific situations. Looking at the table below, against righties Williams has much worse results with his fourseam when he is behind in the count:
| Fourseam | First Pitch | Williams Ahead | Williams Behind | |||
| Usage | xSLG | Usage | xSLG | Usage | xSLG | |
| Vs RHH | 32%* | .417 | 24% | .178 | 40%* | .698 |
| Vs LHH | 41%* | 1.060 | 39% | .427 | 49%* | .553 |
*Highest usage of mix
Data from Baseball Savant
While pitches typically perform worse when the pitcher falls behind, his fourseam is not playable in these situations.
Against lefties, the fourseam also is not performing well first pitch. This suggests that the pitch may not be the best option for establishing counts since hitters are able to get high quality contact against it early. It might be worth exploring what happens if he starts throwing his curveball more first pitch instead.
When he is ahead in the count against both hands, the pitch performs much better. This ties into the second major step Williams can take: throwing in-zone more.
Throwing In-Zone
It is so important that Williams throws in zone more frequently because his mix performs significantly worse when he is behind in the count. In 2025 his first pitch strike rate was only 58% (worse than MLB average). As mentioned before, his sweeper and his curveball are both stronger pitches than his fourseam. In 2025, he was mixing them with his fourseam first pitch, based on batter handedness. This is smart, as both pitches perform well in zone. However, his zone rates were well below average for both pitches.
So it is vital that Williams is able to throw both breaking pitches in-zone first pitch. If he shows that he can do this, he can also start throwing the curveball more frequently first pitch to neutralize results against his fourseam. Otherwise, if he continues falling behind he will face more fastball heavy counts and suffer.
Can Williams be the Guardians’ Ace?
Williams’ results in 2025 demonstrated that he has upside of a top of a rotation starter. His breaking pitches in particular get above average results and he gets above average swing and miss overall.
However, his consistency remains unproven due to his below average control and fourseam results. For that reason, he remains better suited for a middle of the rotation role.
If Williams can start getting ahead in the count more frequently, he can improve his count leverage and get to his secondaries more. His fourseam may also play better in these counts. As a result, his overall performance would improve and be supported by a stronger foundation.
Until then, Williams looks more like a mid-rotation starter with upside than a well-rounded established ace.