The flagstick-in debate rages on after Francesco Molinari's bomb to win at Bay Hill

Mike Stachura

Golf DigestMarch 11, 2019

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The great debate over whether to leave the flagstick in while putting got another endorsement Sunday when Francesco Molinari holed a swerving 44-footer for birdie with the pin in on the 18th at Bay Hill to cap his closing 64 and the Arnold Palmer Invitational victory. However, one of the world’s leading putting instructors and the resident expert on putting at the TPC Sawgrass thinks the flagstick’s value just might end up being more mental than physical.

Mike Shannon, the PGA professional and putting instructor at the PGA Tour’s Performance Center at the TPC Sawgrass, will be watching intently what the those in the field do this week at the Players Championship. But Shannon, who’s worked with more than 150 tour pros, already has been conducting research with local players that shows a trend in how the flagstick is seen both as a benefit and a detriment.

He’s seen three distinct takeaways from leaving the flagstick in:

“Almost 70 percent of the players thought that keeping the pin in from outside of 10 feet gave that player better depth perception, which resulted in better speed and distance control,” Shannon said. “But then inside of 10 feet, a majority of players felt that it actually made the cup look smaller, and they found they had a harder time with the shorter putts.

“The thing that really was impressive about this though was that almost 90 percent of the players thought that having the pin in acted as a plumb line, and so it gave better perception on the slope of the greens. They all felt like they were better readers of the break of the putt when the pin was in.”

Molinari celebrates holing a long putt for birdie on final hole that helped him win the title at the 2019 Arnold Palmer Invitational. 

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Molinari was of at least two minds when it came to his putt on 18. He said his brother, Edoardo, has produced research questioning the value of leaving the flagstick in, and those findings mirror the research conducted for Golf Digest by Tom Mase, a professor of mechanical engineering at California Polytechnic State University. The research project from Cal Poly showed that breaking putts were holed 80 percent of the time with the flagstick out, but only 56 percent of the time with the flagstick in. The full findings of the Cal Poly research will be in Golf Digest’s May issue.

“[Edoardo]’s probably going to tell me off when I speak to him later,” Francesco said. “But, no, I usually always take it out, but when you have a 43-, 45-foot putt, I don’t think it has a massive influence one way or the other. Especially if you hit it at a decent pace, it’s going to go in no matter what. So I thought for a second to take it out, but then I thought maybe it was going to help me to judge the lagging better, so it worked out all right.”

Shannon believes the flagstick-in debate is a living research project this year whose results are as changeable as a Sunday leader board.

“What the concrete evidence is and what the feel of the players is seems so much different,” Shannon said. “Once we get to the end of year, we might know a lot more about it. But it’s fun right now to watch it.”

For now, Shannon is taking the approach that what he tells a student about the flagstick depends on what they’re struggling with in their putting.

“If a player comes in with an excessive amount of three-putts, if that tends to be the issue, I’m probably going to recommend that they keep the pin in,” he said. “But if the player is missing a lot of short putts, I think we’ll go ahead and pull that flag out. And then if they’re having issues with the read, then we might keep it in there, too.

“Fact is, it’s an opportunity we’ve never had before, and we’re just now finding out how to deal with it.”