Second round leaderboard:
-13 R Fowler (US) -10 J Rose (Eng) -9 T Petrovic (US), J Furyk (US) -8 J Day (Aus), S Levin (US) -6 P Mickelson (US), S Levin (US) -5 T Pernice Jr (US), M Kuchar (US), S Stricker (US), K Perry (US)
Selected others:-4 R McIlroy (NI) -3 T Woods (US) -1 M Laird (Sco)
Level B Davis (Eng)
Fowler still needs to go through qualifying on Monday for the US Open
American Rickie Fowler fired a six-under 66 to lead the Memorial Tournament at Muirfield Village by three shots after two rounds in Ohio.
The 21-year-old, following up his first-round 65, made three late birdies to finish ahead of England's Justin Rose (69) and Tim Petrovic (66).
World number one Tiger Woods, defending his title, made the cut after finishing with a respectable 69 to trail by 10.
Phil Mickelson was at six under having posted a one-under round of 71.
Mickelson, who can move to number one in the world with a victory unless Woods finishes outright fourth or no worse than in a three-way tie for third, began the day with two birdies before a storm suspended play for 15 minutes.
His second round score saw him finish the day seven shots off the lead.
Competing for the first time after missing three weeks with a neck injury, Woods made six birdies to scrap his way to the third day of action and complete only his 11th full round of the year.
The American, playing in his final event before the US Open, was content with his form.
"It was decent today," the 14-time major winner said. "I hit more good shots than Thursday and really putted well. I had five lip-outs, so it could have been a pretty good number."
Fowler, who lost in a play-off on the PGA Tour last year and was runner-up in Phoenix this year, continued his fine form from the first round to finish the day on 13 under.
Having tied the 36-hole record at the Memorial set by Scott Hoch in 1987, Fowler said: "Just being in contention the few times I have over the last eight months, this is by far the best I've felt."
Rose, still searching for his first PGA title, had topped the leaderboard with Fowler after a stunning first-round 65.
He carded two bogies on Friday but bounced back to finish the day with his fifth birdie at the par four 18th to stay in the hunt.
Despite being three shots back from Fowler, Rose was not downcast at not matching the rookie for a second day.
"In some ways, I knew that wasn't really an option for me today," said Rose.
"I knew the course was going to play tougher this afternoon. In some ways, I knew my challenge today was going to be a little bit different, just to almost keep myself in the tournament, not get too far behind.
"I was probably more pleased with today's three under than yesterday's seven under."
US pair Petrovic and Jim Furyk are both four shots off the lead having ended day two, nine under par.
Among the players who missed the cut was South Africa's Ernie Els.