First round leaderboard:
-6 JB Holmes (US), R Allenby (Aus) -5 J Bohn (US), B Crane (US), H Slocum (US), L Donald (Eng), R Imada (Jap), K Perry (US), R Moore (US), L Westwood (Eng) Selected others: -3 R Fisher (Eng), S Garcia (Spa) -2 T Woods (US), P Mickelson (US) Level J Rose (Eng), I Poulter (Eng) +1 R McIlroy (NI), P Harrington (Ire), G Owen (Eng) +2 E Els (SA)
An out-of-sorts Woods missed the cut last week at Quail Hollow
Tiger Woods fought back from last week's missed cut with a first-round 70 to lie four shots off the lead at the Players Championship in Florida.
Woods will be toppled as world number one for the first time in 258 weeks if Phil Mickelson, who was also two under, wins and Woods ends lower than fifth.
Australian Robert Allenby and American JB Holmes lead after six-under 66s.
England's Luke Donald and Lee Westwood both shot 67, but Northern Ireland's Rory McIlroy was one-over after a 73.
McIlroy fired a course-record 62 at Quail Hollow last week to capture his first PGA title and become the youngest winner on the Tour since Woods in 1996, but he struggled on an overcast, humid day at Sawgrass.
You don't often get to see this course with hardly any wind and soft greens and it was nice to take advantage
"I found it quite tough to get anything going and struggled to read these Bermuda greens," said the 21-year-old.
"There was definitely a different atmosphere to Sunday. I hit it OK apart from a terrible shot on the eighth and it's so bunched that a good start tomorrow can get me into the top 20."
Woods, who missed the cut for only the sixth time in his career at Quail Hollow, carved his opening drive into trees on the left but battled hard to make birdies at the ninth, 11th and 15th before finishing with a bogey after finding water off the tee at 18.
"I hit some good shots and kept myself right in there," said Woods, who carded 74, 79 at Quail Hollow in his second tournament back after a five-month break following a sex scandal. "The difference is what can happen in a week - that's the way it goes.
Allenby carded just one bogey during his impressive round
"I've played six rounds of golf in seven months, so I think people need to be a little bit more realistic about where I am."
Joint-leader Holmes utilised the early, humid conditions with a slight breeze to card a bogey-free round.
"It was a fun day, one of those rounds where everything was going pretty good," said the 28-year-old.
Fellow leader Allenby had to contend with an afternoon breeze during his round, but the Australian found the course to his liking.
"The greens were a bit slow out there, definitely quite soft after the rain that we've had the last couple of days," said the world number 16.
"It definitely made it very accessible, some of those flags. I'm happy with the start, just happy to be amongst it."
Masters champion Mickelson, who has never held the world number one spot, struggled to find his best form at the tournament widely considered the "fifth major" by the players.
"Shooting 70 today isn't the round that you want," said Mickelson. "There wasn't much wind, the greens were receptive, and there were a lot of low scores.
"The reason I think this was a good day for me is I just didn't have it... and yet I was able to shoot a couple under par. If I can come out tomorrow, get hot and shoot something in the mid-60s, I can get back in the tournament."
Donald, runner-up in Florida in 2007, had four birdies in five holes around the turn and after bogeying the 15th hit a superb approach to six feet on the formidable 462-yard last and made the birdie putt.
"You don't often get to see this course with hardly any wind and soft greens and it was nice to take advantage," said Donald. "At the 18th you'd take four pars every time."