An stayed in touch with Todd thanks to a run of four successive birdies from the 13th which helped him to a four-under 66, but Fowler (69) struggled a little on the back nine where he had two bogeys to drop off the pace after playing the front nine in three under to briefly take the lead at one stage. I feel like we've made a step forward. "So, 3 under for the tournament, although I'm eight back, I feel like I'm in a position that if I can get a hot round, and I've certainly shot some of those over the years, if I get a hot round tomorrow, I can move right up into contention for Sunday, which is what I would love, just to have a chance on Sunday".
"I've got 36 holes to go, man, I ain't anxious". "Bonus birdie there, but that's what you've got to do to win golf tournaments sometimes and that's how you shoot low rounds".
Justin Thomas, who can become No. 1 in the world with a victory here, was fifth at 8 under after a 66.
Koepka had the lead at 10 under before falling apart on his back nine with a double bogey and two bogeys.
If a cut had been in operation, among the big names who would have missed it would have been Spain's Jon Rahm, the new world number one, who carded a four-over-par 74 and plummeted 26 places down the leaderboard into a tie for 62nd place.
The 35-year-old American, who converted an impressive 50-foot birdie putt over a slope at the par-three 14th, walked off the course feeling better than ever heading into the weekend.
Fowler holed out from the green-side rough on the par-5 third to pull within two. He sank a 12-footer on No. 15 to open a four-stroke lead until Fowler's birdie-birdie finish. He hit his second shot from 190 yards to 9 feet and made the putt for birdie.
"That's the easiest to put on the green, to not hit in the water", Todd said.
"It's been nice to see some putts go in", Fowler said. "These greens are about as good as they get".
Jodi Ewart Shadoff of England also played bogey-free for a 67 in the LPGA Tour's first event since February.
After setting a course record with a 10-under 62 in the opening round at the Forest of Arden Marriott Hotel and Country Club, Garcia Rodriguez cooled somewhat in the second round with a 3-under 69 that included birdies on the last two holes.
Brendon Todd is one of three players who have won twice on the PGA Tour this season, and he's looking for more.