Phil Mickelson has a logo on the back of his golf shirt and shoes, and you might not have seen it previously. So you're wondering what it is.
That logo on his shirt and shoes is his personal logo, and it is a silhouette version of his jump as he made the putt to win the 2004 Masters, his first major.
Mickelson started using the logo in 2017 on his rain gear, but he has actually been using the Mickelson jump silhouette in his golf-course design business and on his personal website for a while now. He had it on his clothing for a while in 2017, then it came off, and now it's back.
According to Golf Channel in 2017, Mickelson said the logo is part of a project coming out later in the year and he wasn't ready to talk about it. He's been coy about the logo and why he uses his 2004 Masters silhouette logo, it's clear he wants people to know about it.
We do know Mickelson uses his jumping logo in association with his golf-course design and architecture business, and he has a handful of projects either ongoing or upcoming. So this may be a promotion of that, especially since there's not really any merchandise for sale featuring that logo.