I'm lucky enough to work with the PGA Tour's ShotLink staff (the guys who measure every shot by every pro in every tournament), and I've been taking a hard look at their mid-season report. I've paid particular attention to the stats most likely affected by the USGA's new groove rule. Here's what the data reveals.
PGA Tour Players scrambled slightly better with the new, less-aggressive wedge grooves in the first half of 2010 compared to the first half of 2009, whether they were scrambling from the sand, rough or fringe. The improvement didn't happen because the pros were making more one-putts, but rather because they pitched, chipped and blasted shots slightly closer to the hole in 2010. Even on longer wedge shots, the new grooves failed to keep the big boys from knocking the ball closer to the hole.
You might think that driving stats have little to do with the USGA's new groove rule, but remember: The USGA changed the rules to make pros suffer more when they missed fairways, with the thinking that shots from the rough with lower-spinning wedges would be harder to stop closer to the hole. This, however, hasn't seemed to change the average Tour player's strategy. In fact, driving distance and accuracy are almost the same between last year and this year.
Although the stat differences between 2009 and 2010 are small and can possibly be explained by other parameters, I can safely draw an important conclusion: New grooves have made little impact on Tour, because the pros practiced with the new wedge grooves more, and did so earlier in the year than in previous seasons. They knew the change (less spin) was coming, and they prepared for it.
What remains to be seen is how the new groove rules will affect you. My guess is that, unlike the pros, you'll be hit hard. One reason is that you hit more wedges into greens than Tour players do (because you miss more greens on long shots), so the rule will have a greater impact. Second, you'll probably never find enough time to sufficiently practice and learn how to compensate for your loss in wedge spin. As more and more amateurs begin to put new-rule wedges into play, you'll start to see more and more shots bouncing and rolling over the green. I hate to say it, but the pros have learned how to play around the USGA's changes, while you'll probably end up taking it "on the nose" unless you make wholesale changes to your practice habits.