DETROIT — Earlier this week, Jo Adell retreated to the batting cage with his headphones and a tee. He spent 30 minutes simply hitting balls off a tee. “Just kind of got back in my groove,” Adell said.

SILVIS, Ill. — The tiny gray trailer parked at the entrance of the TPC at Deere Run doesn’t look like much, but it is the nerve center for a fleet of 183 vehicles and 109 drivers responsible for ...