Seamus Power was unable to match his opening day exploits at the Rocket Mortgage Classic in Detroit, but remains just three shots adrift of the lead after a second round 71.
The Waterford man began the tournament with a bogey-free 65 in a share for fifth, and while he dropped just one shot yesterday, at the par-4 473-yard 12th hole, birdies were harder to come by.
The 34-year-old picked up shots at the 7th and 14th to move to seven-under par, three shots adrift of joint-leaders Tom Lewis and Chile's Joaquin Niemann.
After carding a stellar seven-under 65 on Thursday, Lewis was steady on Friday, picking up three birdies in a bogey-free round to improve to 10 under at the half-way mark of the tournament.
Niemann mirrored Lewis's scores to also sit one shot clear of chasing Americans Troy Merritt, Chris Kirk and Max Homa.
Scotland's Russell Knox is two shots back from the leaders after improving on his opening round score of one under with a seven-under 65 on Friday.