Kevin Harvick led the first of two Saturday practice sessions at Pocono Raceway with a lap of 174.965 mph.
Erik Jones was second fastest at 174.931 mph with Ryan Blaney third quickest at 174.402 mph. Denny Hamlin clocked in fourth at 173.826 mph, and Clint Bowyer rounded out the top five at 173.404 mph.
William Byron (173.320 mph), defending race winner Kyle Busch (173.304 mph), Daniel Suarez (173.160 mph), Martin Truex Jr. (173.104 mph), and Chase Elliott (173.034 mph) completed the top 10.
The 50-minute session had just one issue when JJ Yeley spun in Turn 2. Yeley escaped without contact to his No. 23 Toyota.
Harvick, Hamlin, Byron, and Chris Buescher were among the drivers who served 15-minute penalties.
Harvick is still looking for his first win at Pocono.
UP NEXT: Final practice at 11:40 a.m. ET.