His high-arcing approach never left the flagstick, landing 5 feet past, spinning back, flirting with the cup, and causing the crowd to hold its collective breath, then rumble in anticipatory unison.

But the ball rolled 2 feet by the hole, leaving a birdie putt that Cantlay would make, giving him a 10-under-par 60, the lowest PGA Tour score ever by an amateur. Just 19, he also led the tournament after two rounds.

What a difference a year makes.

Fifty-two weeks after his 60, almost to the day, Cantlay stood once again in the 18th fairway in the second round of the Travelers, boiling in the late-morning heat, sunglasses hiding his disappointment. His 59th swing

had come two holes earlier. Instead of the lead, the 18th-hole birdie this time - his approach again settling 2 feet away - only meant that Cantlay would miss the cut by two shots.

Cantlay is no longer a 19-year-old amateur. He is a 20-year-old professional who made his for-pay debut at the Travelers, shooting 75-67 and leaving early, empty-handed.

Exempt into last week’s US Open if he remained an amateur because of his runner-up finish in last year’s US Amateur - he tied for 41st at the Olympic Club - Cantlay thought the time was right to leave school early and launch his career. The venue and tournament had a hand in the decision.

“This timing makes sense for me, being able to start somewhere where I’m comfortable and I have good memories,’’ Cantlay said before the tournament. “I feel ready and comfortable with being a pro and trying to be as good as I can be.

“When I talked it over with my mom and my dad and [swing coach] Jamie Mulligan, we thought Travelers, since I played well here last year and it’s after the US Open, it was the right time. That’s kind of why I’m doing it now.’’

Cantlay will be represented by Mark Steinberg and Excel Sports Management, an agent and firm with a growing list of professional golf clients, including Matt Kuchar, Gary Woodland, and Tiger Woods.

Joining the stable is Cantlay, fresh off two years at UCLA - he’s the Bruins’ career scoring leader (70.7 average) - and a decorated amateur career that had him ranked as the world’s best nonprofessional.

He has already shown that he has the game to compete in PGA Tour events. Cantlay was low amateur at last year’s US Open and this year’s Masters.

Last year’s Travelers - he tied for 24th after closing 72-70 - was part of a four-tournament summer run in which he also tied for 21st at the US Open, tied for 20th at the AT&T National, and tied for ninth at the Canadian Open. Had he been competing as a professional in those tournaments, Cantlay would have earned $356,297.

The money would have been nice. But playing as an amateur, Cantlay said, brought with it certain advantages.

“As an amateur, you don’t feel like you’re losing anything,’’ he said. “I got to a hole at the US Open, my caddie turns to me and goes, ‘Why not hit driver? You’re an amateur. It’s not like you’re going to lose anything.’ ’’

He’s not in that position anymore. Cuts made means money, while missed cuts go down as missed opportunities.

Cantlay may have said after Saturday’s 67 that he didn’t feel different - “inside the ropes it’s the same, I’ve still got my carry bag’’ - but others who played in PGA Tour events as amateurs before turning pro said the circumstances aren’t similar at all.

“It’s quite a bit different. It’s totally different,’’ said Hunter Mahan, who played the Travelers as an amateur in 2000, then won in 2007, his first professional tour victory.

“When you’re an amateur, you’re just playing to win and trying to play well. When you turn pro, obviously there’s responsibilities and there’s decisions to be made.

“There’s a lot more decisions in life, and sometimes your golf takes time to adjust to it.’’

One tournament into his career, Cantlay wasn’t about to draw any conclusions. Everybody misses cuts. His first as a pro just came under a brighter spotlight, at a place where he made history.

“I struggled the first day and never really recovered,’’ Cantlay said. “I didn’t make very many putts. I hit a lot of good ones, just none went in. That’s kind of how golf goes sometimes.

“Everything feels really good right now. I played a pretty good second round, so things are heading in the right direction.’’

He’s headed to next week’s AT&T National, where he hopes to cash his first check. As a nonmember of the PGA Tour, Cantlay can accept five more sponsor’s exemptions this season, and will need to climb to at least No. 125 on the money list to automatically earn his tour card for 2013.

If Cantlay wants to avoid Qualifying School and make the rare jump straight to the PGA Tour, he’ll need some decent finishes. Last year it took $668,166 to finish 125th; in 2008 the amount needed was $852,752.

It’s a substantial amount of financial pressure on a young professional. But Cantlay seems unfazed. He’s confident with his decision, and has talked to a number of players who’ve made the leap.

“They’ve helped me a lot, [told me] just to embrace it,’’ Cantlay said. “Because it’s really fun what we get to do, play golf all the time. So keep it fun.’’

Michael Whitmer can be reached at mwhitmer@globe.com. Follow him on Twitter @GlobeWhitmer.