Still, the top two draws in American golf were tantalizingly close to the lead at the Farmers Insurance Open at Torrey Pines.
"I'm confident heading into the weekend," said Mickelson, who fired a second-round 69 despite struggling off the tee.
He and six others were at 8 under, three behind leader Bill Haas, who fired a 66 on the South on Friday.
Haas is coming off a second-place finish at the Bob Hope Classic last week, and a two-win 2010 (Hope, Viking Classic).
Anthony Kim, finally playing without pain in his thumb, birdied his first four holes and shot a 5-under 67 on the more difficult South Course. He was in second alone at 9 under.
Playing with Kim and Rocco Mediate, Woods birdied four straight holes on the front nine, but faltered by going three-over in a five-hole stretch that could have been worse.
Twice he failed to escape greenside bunkers, on the 11th and 14th holes, but splashed out and saved bogey both times.
The six-time Farmers winner recovered with birdies on 16 and 18, and his second-straight 69 put him at 6 under, five back.
"I lost it in the middle part of the round," Woods said, "and then I got it back at the end."
The widely reported demise of the American Tour pro has been slightly exaggerated, if Friday's results are to be believed.
Six of the seven at 8 under are Americans, including not just Mickelson but also John Daly (69), Rickie Fowler (71), Hunter Mahan (67), Bubba Watson (65) and defending champion Ben Crane (66). Sweden's Fredrik Jacobson (69) also was at 8.
"Feel solid," said Daly, who made a double bogey after four-putting on No. 4, his 13th of the day, but bounced back with a birdie two holes later. "Hitting the driver real solid and everything's just solid. That is something that I haven't had in a while. I think a lot of that is trying to overcome injuries and stuff."
A year after only three of the top 20 ranked players bothered to show up, the Farmers could be heading toward an epic weekend.
Woods, who was headed to the driving range after his round to make a few corrections, was pleased with his finish after bogeys on 11, 14 and 15 knocked him off the first page of the leaderboard.
His swing change under new coach Sean Foley is still a work in progress, but all things considered it seems to be working.
"I have to be patient with the process," he said. "It doesn't happen overnight. I know it's in there because I can hit some really sweet shots like I did at 18, but it's a matter of more work, more reps, and more comfort."
Mickelson's inspired play has been a particularly pleasant surprise, given his bittersweet 2010, when he won the Masters but couldn't seem to get it together anywhere else but Augusta.
With his wife, Amy, watching the first two rounds from outside the ropes, Phil has scored well despite not having his "A" game. Now the three-time Farmers champion, who limped in at 19th here last year, has to find a way to win on the South Course, which he hasn't done since Rees Jones redesigned it for the 2008 U.S. Open.
"I am looking forward to it," Mickelson said. "I feel like I have a decent idea of how I want to play the golf course."
As it did in the first round, the South Course played nearly two shots tougher than the revamped North.
Fowler, who tied for fifth last season when he was Rookie of the Year, made four birdies and three bogeys on the South, posting a relatively pedestrian 1-under 71 after shooting 65 on the North.
Watson, who missed the cut at the Hope last week, matched Fowler's 65 on the North on Friday, the low round of the day.