Adam Scott, at press time two shots off the lead at the PGA Championship behind Brooks Koepka, is using a long putter. It is actually one of two putters in his bag, as noted by Golfweek.
The long putter is legal because it is not anchored to Scott’s chest, but that doesn’t mean it’s not controversial. If you’re on social media, you’ve seen lots of commentary, or even wondered yourself about it. European tour pro Matthew Baldwin wondered aloud about its legality at The Open in a since-deleted tweet.
The controversial putting style was brought to prominence by Bernhard Langer and Scott McCarron.