Stewart-Haas Racing teammates Daniel Suarez and Clint Bowyer were the fastest in the first of two practice sessions Friday at Michigan International Speedway.
Suarez topped the leaderboard at 188.882mph (38.119s), with Bowyer, the defending race winner, second quick at 188.659mph.
The rest of the top five were Austin Dillon at 188.501mph, Joey Logano at 188.034mph, and Kyle Larson at 187.901mph.
Six through 10 were Erik Jones (187.877mph), Brad Keselowski (187.808mph), Kurt Busch (187.490mph), Paul Menard (187.251mph), and Ricky Stenhouse Jr. (187.246mph).
Denny Hamlin was 21st fastest and ran the most laps of any driver at 39.
There are 36 cars entered in the FireKeepers Casino 400.
UP NEXT: Final practice at 4:05 p.m. ET.