Editor's note: This story was originally published on Tuesday. Since then, the PGA Tour clarified on Wednesday that Wyndham Championship winner Si Woo Kim, 21, of South Korea, is also a rookie. Originally, the PGA Tour's media guide indicated that Kim's rookie season came in 2013. He is still alive in the PGA Tour playoffs -- along with Emiliano Grillo and Smylie Kaufman -- and is ranked 18th in the FedEx Cup standings, giving him a strong shot at rookie of the year honors and making it to the Tour Championship.
NORTON, Mass. -- Since the PGA Tour playoffs started in 2007, picking the year's top rookie has mostly been a no-brainer.
This year, it won't be so easy.
That's because Argentina's Emiliano Grillo and American Smylie Kaufman are the only two rookies to win on tour in the 2015-16 wraparound season. Typically, after the victory criterion, the main way to separate yourself is if a player qualifies for the 30-man field at the Tour Championship.
With two playoff events left, Kaufman and Grillo are the only rookies remaining. In the FedEx Cup era, more than one rookie has never reached the Tour Championship, so each rookie to make it to East Lake won the award.
Although Grillo admits he hasn't thought much about taking home the honor, he wouldn't mind the recognition that comes with being acknowledged by your peers.
"I know it's there," said Grillo about the award, which is voted on by PGA Tour players. "I just know good game will take care of it. ... It's my first year. It's nice to accomplish something."
Grillo is almost assured of making the playoff finale at eighth in the FedEx Cup standings heading into this week's BMW Championship, while Kaufman is on the bubble at 33rd.
Kaufman's victory at the Shriners Hospitals for Children Open in October got him in the top rookie conversation, but one of the rounds he's least likely to forget was playing in the final pairing on Sunday at the Masters in April. Those are great learning experiences, but finishing in a tie for 29th at Augusta doesn't separate you from the competition.
Speaking of the majors, that's where Grillo stood out from his fellow rookie. The 23-year-old Argentine was one of just 14 pros to make the cut at all four majors. In his career, Grillo has played five majors in total, playing all 72 holes each time.
Not only did Grillo make that list of major weekend players but, when you dig deeper into those numbers, the golfers with the best average finish in 2016 were Jason Day (10.5) and Jordan Spieth (20.5). Next on the list? Grillo at 24.0.
If you look at lowest aggregate score in all four majors, Day runs away with the title at 9 under. Spieth was No. 2 at 3 over. Next closest? Grillo at 10 over. Only Spieth (at the Masters and the PGA Championship) and Grillo (at the Open Championship and PGA Championship) finished multiple majors under par in 2016.
"Get another win is the next goal, that's for sure," said Grillo, who won the Frys.com Open in October. "Contending more often in the majors, that's the next one. I did it at the Open [Championship], I did it at the PGA Championship, and it felt great. Of course, I'm looking for more. You're always looking for more."
Previous winners of the PGA Tour Rookie of the Year award include Vijay Singh (1993), Ernie Els (1994), Tiger Woods (1996), Rickie Fowler (2010), Keegan Bradley (2011) and Spieth (2013), so either player will be in good company.
But what makes a rookie a rookie? It's not as complicated as the Rules of Golf, but it's close.
According to the PGA Tour, the rookie season for a golfer kicks in when a player tees it up in 10 or more events as a PGA Tour member or special temporary member. Or he finishes inside the top 125 on the FedEx Cup points list, or the Top 125 on the official money list. Or if he's inside the top 125 on the nonmember list. And if a golfer played in more than seven official PGA Tour events in any prior season, he's not eligible for the award.
Got that? Good, because I'd bet many a pro couldn't tell you when his official rookie season occurred.
If the fans got to vote, judging by the vocal following Kaufman had outside Boston, where he finished T-24 at the Deutsche Bank Championship on Monday, the LSU product would be a shoo-in to win. For a while at TPC Boston, Kaufman looked as if he was going to contend for the victory, but a final-round 76 that included a back-nine 40 derailed those hopes.
If neither wins one of the last two playoff events, look for Grillo to get the nod with his major championship showing in 2016 being the difference.
Does the Argentine let his mind wander a little and think about the FedEx Cup bonus plus the winner's check if he were to win the Tour Championship, which would clearly give him the rookie award?
"Oh yeah, you think [about] it every single day," he said.
But would it change anything?
"No, definitely not. But it would add 12 million things to my confidence, that's for sure."