Germany's Alex Cejka grabbed the first-round lead at the Verizon Heritage event as Jose Maria Olazabal found his way onto a leaderboard again at Harbour Town Golf Links.
As the PGA Tour resumed play following last weekend's Masters, Cejka shot a bogey-free seven-under-par opening round of 64 on Hilton Head Island in South Carolina while Spanish veteran Olazabal shot a three-under 68 as both continued comebacks from injuries.
Ireland's Rory McIlroy finished with a one-over-par 72.
Cejka leads the tournament by one stroke from American Lee Janzen, who fired a 65, the two-time US Open champion posting an inward nine of 31 having started on the 10th tee for only his fourth sub-70 round of the year.
The German is still recovering from neck surgery he underwent last September having pinched a nerve at the Open last July and he returned to action at the start of the year looking only to get fit.
"My goal is to stay healthy," Cejka said. "The last couple of years, I've been a little bit unlucky, a little bit injured. I had the neck surgery, also, where I was off for three months.
"I just lost all my strength in the left side. So it was tough to come back.
"So just hopefully everything stays well and I get healthy and practice hard.
Olazabal's battle with rheumatism has been longer lasting and the two-time Masters champion has been restricted to six appearances in each of the last two years.
The 43-year-old Spaniard returned to action this year on a major medical extension in the US, reappearing at the Masters where he missed the cut.
He made amends on Thursday, however, with a one-bogey, four-birdie 68 to end the first round in a tie for sixth place, four strokes off Cejka's lead.
"It's a golf course where you have to hit it really straight off the tee with its narrow fairways and very small greens," Olazabal told PGA Network Radio.
"If you don't strike the ball well you're not going to score but I managed to do that today, keep the ball in play and make a couple of putts. That was it.
"I haven't been able to play for more than a year and I need to do the best I can and that's what I'm going to try to do this week.
"I've been as healthy as I can remember and for the last three weeks it's been good. It hasn't been like that for a long time so I want to try to make the best use of it."
South Africa's Trevor Immelman failed to successfully defend his Masters title at Augusta but put disappointing early-season form behind him to finish in a tie for 20th in the opening major of the year.
That good form continued at Harbour Town where, despite closing with a bogey five on the ninth hole, Immelman shot a five-under 66 to finish the day in third place.
Americans Ted Purdy and Brian Gay finished a further shot behind with 67s with Olazabal part of an 11-man group on three-under that also included Ernie Els of South Africa, Australian trio Rod Pampling, Aron Price and Stephen Leaney and Americans Bob Estes, Bill Haas, Todd Hamilton, Cliff Kresge, Jeff Maggert and Tim Petrovic.
England's Greg Owen shot a 69 alongside, amongst others, defending champion Boo Weekley, who is chasing a hat-trick of successive wins in the tournament.
Camilo Villegas of Colombia, American Zach Johnson, Rory Sabbatini of South Africa and Nathan Green of Australia were among those who carded 70s while Daniel Chopra of Sweden, England's Brian Davis and India's Jeev Milkha Singh were in a big group that shot level-par 71s.