Jason Day can steal Player of the Year honor from Jordan Spieth at season finale

Billy Horschel won’t be at East Lake this week to defend his title, but the 2014 FedEx Cup champion will follow the action carefully since his choice for Player of the Year honors appears to depend on whether Jordan Spieth or Jason Day wins the PGA Tour’s season finale.

Rory McIlroy and many others considered the ballot box stuffed and locked after Spieth won two majors this year.

“No way,” the winner of four grand slam events said last week about Day’s chances to grab the award. “Majors trump anything,” said McIlroy. “Jordan has had that locked up basically since the Open Championship.”

Horschel, though, hinted during a tweet-a-thon with Twitter followers on Tuesday that some last-minute lobbying by Day, likely in the form of a sixth W for the 2015 campaign, could sway the swing votes.

Remember about two months ago — before the NFL relegated watching Sunday golf to quick peeks during commercial breaks and halftimes — when two-time major champ Spieth could pretty much toss his cap onto the tee of any tour event and walk away with the PoY award? As the curtain is finally set to drop on the seemingly endless 2015 PGA Tour season (before the next one opens in three weeks), Day may pull an upset if he emerges triumphant from Atlanta.

Day, thanks to sizzling play that began by missing the British Open playoff by one stroke and culminated (so far) with last week’s dominating six-shot win at the BMW Championship, bounded past Spieth and Rory McIlroy to ascend to the top spot in the world rankings for the first time in his career. For sure, he has played like No. 1 for much of the summer, winning four times in his last six starts, a stretch that included his first major win at the PGA Championship.

The 27-year-old Australian also had top-10 finishes at the British and U.S. Opens — a T9 at the latter after fighting vertigo at Chambers Bay.

Then there is Spieth, who also missed overtime at the Open Championship by a shot after winning the Masters and U.S. Open. In addition to two other tour wins, Spieth was runner-up to Day at the PGA.

So, case closed on the PoY debate for many.

Except for those back-to-back missed cuts to kick off the postseason. Combine them with Day’s sizzling summer, which so far includes Ws at The Barclays and the BMW, and what seemed a no-brainer not that long ago has become a true puzzler.

A sixth calendar-year victory for Day, who also won the Farmers Insurance Open back in February, would surely give his tour peers — who will determine the PoY winner — reason to check his name on the ballot.

“I still think it’s him,” Day said Sunday about Spieth’s position in the PoY chase. “But I’m hoping that I can go and win next week and get people talking about it a lot more.”

Prevailing at East Lake and capturing the FedEx Cup title “might change some people’s minds,” said Day.

A win by Spieth would put an exclamation mark on a remarkable season for the 21-year-old Texas Longhorn and an end to any suspense about the outcome of the PoY race.

The two contenders — and Nos. 1 (Day) and 2 (Spieth) in FedEx Cup points — will have at least one more opportunity to assess each other’s game when they play together on Thursday. Thanks to their standings since the playoffs started, their 2 p.m. ET tee time will mark the fourth straight event in which they will go head-to-head to open a postseason tournament.