Seamus Power dropped further down the standings at the St Jude Classic after a third round of 70 left him nine shots behind co-leaders Dustin Johnson and Andrew Putnam.
Bogeys on 17 and 18 proved costly for the Irish player and he now sits on six-under. Shane Lowry carded a 68 to lie on three-under, while Padraig Harrington is one-over after his round of 71.
Johnson's hopes of reclaiming the world number one spot remain on track after shooting a third round of 65 to keep hold of the lead.
The American, who will retake the ranking ahead of next week's US Open if he posts victory in Memphis, fired six birdies - four on the back nine - and just one bogey to finish on 15-under overall.
He was forced to share his spot at the top of the leaderboard, however, after compatriot Andrew Putnam carded a superb 6-under 64 for the second round in a row.
His bogey-free round featured six birdies, including a 22-foot birdie putt on the par-4 12th.
The pair sit five shots ahead of third-placed Stewart Cink, whose round of 64 included a hole-in-one on the par-3 8th.
Richy Werenski and Wesley Bryan are a shot further back.