A woeful performance on the greens has prompted Tiger Woods to spend considerable time practising his putting after the second round at the BMW Championship in Philadelphia.
A day after opening with a course-record equalling 62 at Aronimink Golf Club and sharing the lead, Woods stalled during an even-par 70 that left him at eight- under-par and five shots off the pace.
Woods is still in the mix despite Xander Schauffele (64) surging into the outright lead at 13 under at the elite 70-man event - the penultimate leg of the $US67 million ($A93 million) FedEx Cup playoffs.
Justin Rose sits two shots back in second following his 63, while Rickie Fowler (65) and Hideki Matsuyama (64) headline a four-way tie for third at 10 under.
Five-time BMW winner Woods was solid from tee to green, hitting 11 of 14 fairways and 14 of 18 greens in regulation.
But the longest putt he made on day two at Aronimink was six feet.
"I hit it just as good (as the opening-round 62) and putted just as good, but nothing went in and that's the way it goes," a frustrated Woods said.
"That round today (could have) easily been six or seven under; it turned into even par which is not what I needed to do (when) everyone is going low and birdies should be had."
Woods implored himself to hole more putts with forecasted Friday night storms expected to further soften conditions at Aronimink.
"I've got to make birdies and try and keep pace; this golf course is playing soft and tomorrow will be the same thing," Woods said.