Justin Thomas
Changed Putter
at a Major.
Then Won It.
We’ve looked at Rahm’s mid-round switch and Morikawa’s inconclusive search. Both told the same story: spikes that normalise back to baseline. Then there’s JT.
Traditional stats like putts per round or greens in regulation tell you what happened. Strokes Gained tells you how much it mattered relative to the field.
The concept, developed by Columbia professor Mark Broadie, compares every shot against the statistical average outcome for all Tour players from that same position. Make a putt from 15 feet when the field averages 1.7 putts from there, and you’ve gained 0.7 strokes. Miss it and you’ve lost 0.3. Every shot on every hole, across every round, summed into a single number.
How many strokes per round a player gains or loses on the greens versus Tour average. The core metric throughout this series. Positive = better than field. Negative = worse.
Measures how much closer to the hole a player leaves their approach shots versus Tour average from the same distance and lie. The strongest single predictor of Tour earnings we’ve found.
Captures chipping, pitching, bunker play — any shot within 30 yards that isn’t a putt. Separates short-game skill from putting, which traditional stats bundle together.
The sum of all four SG categories: off the tee, approach, around the green, and putting. A positive total means the player performed better than the average Tour player across their whole game.
The short version: Strokes Gained is context-aware. Putts per round isn’t — it treats a 3-foot tap-in the same as a 40-foot lag putt. SG accounts for the difficulty of every shot, which is why it’s a far more honest measure of whether a putter change actually worked.
Regression to the mean is the tendency for an extreme performance — very good or very bad — to be followed by something closer to average. It’s one of the most important and most misunderstood concepts in sports statistics.
When a player posts +1.66 SG: Putting in a single week, that’s an exceptional result. The statistical expectation is that the next week — and the weeks after — will be closer to their long-run average, regardless of what equipment they’re using. This isn’t a failure. It’s how variance works in noisy sports.
A player uses a new putter and holes everything for four rounds. It’s tempting to credit the equipment. But statistically, extreme weeks are often followed by more ordinary ones — the putter may have had nothing to do with it.
A real improvement shows up in the long-run average, not just peak weeks. If the average across 10+ tournaments moves sustainably upward after a switch, that’s meaningful. A spike followed by reversion is almost always regression to the mean.
The SC T5.5 Mallet averaged −0.10 for the rest of 2022 after the PGA Championship win. This is the pattern: exceptional week, followed by the player performing at their normal level. The equipment didn’t change. The variance did.
Regression to the mean doesn’t mean the putter wasn’t helpful. It means we need sustained evidence — multiple months, not one tournament — before crediting equipment for a performance change.
We’ve looked at Rahm’s mid-round switch — one exceptional round that didn’t last — and Morikawa’s inconclusive blade experiment — marginal improvement that might just be noise. Both told a version of the same story: a spike that normalises back to baseline. Then there’s JT.
Thomas is a strong putter by Tour standards. His search wasn’t born of crisis — it looks more like a player who felt something better was out there, and was prepared to spend almost a full season finding it. The Futura X5 was neutral for 17 events. The SC Prototype phase showed modest improvement. The Byron Nelson the week before the PGA Championship: T5, +0.85 SG: Putting. The pieces were assembling.
Each dot = one tournament. Red line = 5-tournament rolling average. The circled dot = PGA Championship win week. Hover for details.
Then: new putter on day 1 of the PGA Championship at Southern Hills. +1.66 SG: Putting for the week. Lowest 36-hole score in the field. Wanamaker Trophy.
The rolling average after the win tells the rest of the story — the SC T5.5 Mallet averaged −0.10 for the rest of 2022. This is what regression to the mean looks like in data: an exceptional performance, followed by the player reverting to something close to their long-run average. The same pattern appeared with Rahm’s #7S at Riviera. The same pattern appears almost every time a player has a career week with a new putter.
The difference here: this regression happened after four full rounds at a Major, not one round at a regular event. And the win happened at the end of a deliberate, season-long search — not a mid-round panic switch.
The Verdict
A full season of searching. One week that mattered more than all of it. The post-win regression is real — but it doesn’t diminish what happened at Southern Hills. Unlike every other spike in The Search, this one lasted four rounds, at a Major championship. Sometimes the timing is everything, even if it doesn’t last.
- 01 — Jon RahmThe mid-round switch that worked — briefly →
- 02 — Collin MorikawaWhen the numbers barely move →
- 03 — Justin ThomasYou are here
- 04 — Rickie FowlerThe most complete dataset in the series →
