Niemann and Lewis each shot 3-under 69 on Friday to reach 10-under 134. Troy Merritt (68), Chris Kirk (68) and Max Homa (65) were a shot back.
First-round leader Davis Thompson was one of eight players two strokes back. The 22-year-old Thompson had a 1-over 73, a day after matching a Detroit Golf Club record with a 63.
The wind picked up considerably during the second round with gusts to 25 mph that knocked hats off heads and made the relatively short and easy course more challenging.
Defending champion Bryson DeChambeau, ranked sixth in the world, voiced his frustrations with the unpredictable wind and his shaky game throughout his round.
He missed the cut at 1-under 143, following an opening 72 with a 71.
DeChambeau, who has an endorsement deal with Rocket Mortgage, declined interview requests for the second straight day. His silence left lingering questions about why he parted ways with caddie Tim Tucker on the eve of the tournament.
The surprising split with Tucker also gave Brooks Koepka more fodder for jabs via social media, declaring Thursday as “caddie appreciation day,” on Twitter.
Nearly two weeks ago, the 2020 U.S. Open champion went from leading that same major with nine holes to tying for 26th with a collapse. Despite being a part of lackluster fields, DeChambeau tied for 19th at the Travelers Championship last week and failed to make the cut in Detroit.
PGA Championship winner Phil Mickelson shot a 72 after opening with a 69, making the cut at 3-under 141 and changed his tune about returning to play in Motown.
On Thursday, Mickelson said he will not come back due to a report by The Detroit News that was published earlier in the week. The newspaper obtained federal court records from 2007, detailing how a Michigan-based bookie was accused of cheating Mickelson out of $500,000 about 20 years ago.
After talking with Rocket Mortgage Classic officials and getting a lot of boisterous support from fans, Mickelson told reporters he will come back to compete at Detroit Golf Club next year if 50,000 people sign a petition and each person commits to doing a random act of kindness.
Patrick Reed, who was one of just two players in the field ranked in the top 10, also was on the cut line at 3 under after rounds of 69 and 72.
Masters champion Hideki Matsuyama withdrew Friday after testing positive for COVID-19. The PGA Tour does not test fully vaccinated players.
At least 35 players have had to withdraw because of a positive test and Matsuyama is the fifth in the middle of a tournament since the testing program began last June. The final PGA Tour event for testing, not including the majors, will be the Barbasol Championship on July 15-18.
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