All three were still on the TPC-Sawgrass course when the suspension came shortly before 7 p.m. EST. A storm system blew through the area early in the day, causing a 2 ½-hour delay.
"I don't know if I've ever seen it rain here that hard that quick," said Rocco Mediate, who eventually shot a 1-under 71.
When play resumed, with water still standing in some of the bunkers, blustery winds made conditions difficult. But as the afternoon progressed, the winds calmed and the last few hours of daylight provided an almost perfect opportunity to make birdies.
Mickelson, who began play on the back nine, rolled in a six-foot birdie putt at the par-5 second hole just before the siren blew to end the day. That left him at 5-under with seven holes remaining.
Mickelson had the lead last week at Bay Hill the Bay Hill Invitational before suffering three straight bogeys.
DiMarco was 5-under with five holes left and Hoch was 5-under with six holes to go.
All of the players at 4-under were also on the course at the end of play. They included David Gossett, Steve Stricker, Jerry Kelly and 44-year-old Nick Faldo, a six-time major championship winner who has not claimed a PGA Tour event in five years.
Woods, who won his 30th tour title and first of the year at Bay Hill, played 14 holes Thursday and was even par with one birdie and one bogey. The bogey came at his final hole of the day, the fifth, when he drove deep into the rough and could only chip out.
Woods is trying to become the first player to win this championship two years in a row.
The difficult conditions in the middle of the afternoon caused the field to bunch into a huge pack. At one point there were 13 players tied for the lead at 3-under. Those who managed to complete play at 3-under 69 included Robert Allenby, Jeff Sluman, Mark Calcavecchia, Steve Lowery, Stuart Appleby and current PGA champion David Toms.
They had to fight through the worst of the weather with the winds making the 17th hole, in particularl, difficult to handle. The famed hole with its island green cost Appleby a double bogey when he became one of the more than 30 players to hit their tee shot in the water.
Those still on the course when darkness came will return early Friday to complete the first round and then, after a very short break, embark on their second round. Those who finished their first round Thursday will not begin play until the afternoon.
Although no more rain is in the forecast for the rest of the week, temperatures were forecast to be in the 40s early Friday with winds from the north at 15 miles per hour.
Among the more high-profile players in the field, Colin Montgomerie shot 70, Scott Verplank, Brad Faxon and Retief Goosen all had a 71 and 52-year-old Tom Kite shot even-par 72. Kite was 3-under through nine holes when the rains came, but suffered two double bogeys after play resumed.
Vijay Singh, who was runner-up to Woods here last year, made a quadruple bogey eight on the fourth hole and was 2-over through 12.