Miler suffered the injury during a one-on-one drill when he jumped to catch a contested pass against Pro Bowl cornerback Kyle Fuller and landed awkwardly. He eventually walked back to the locker room under his own power.
Coach Matt Nagy said Sunday that Miller has a sprained ankle but believes the receiver will be ready for Week 1.
Roughly 15 to 20 minutes after exiting the field Saturday, Miller tweeted "I'm good." The tweet, however, was then quickly deleted.
The 51st overall pick of the 2018 NFL draft, Miller suffered a dislocated shoulder against the Arizona Cardinals in Week 3, and it affected him the rest of his rookie year.
Miller technically missed only one game, and he still led the team with seven touchdown receptions -- the most by a Bears rookie receiver since Bobby Engram (six) in 1996 -- but he struggled to run routes the proper way because of complications related to the shoulder injury.
He finished the year with 33 catches for 423 yards, and his seven TDs were second among NFL rookie receivers after Atlanta's Calvin Ridley (10), whose brother, Riley Ridley, was the Bears' 2019 fourth-round draft pick out of Georgia. Miller underwent offseason surgery to fix the shoulder issue and missed Chicago's entire offseason program. He was medically cleared for beginning of training camp in late July.
"When you have reservations about your shoulder popping out, I think anybody would be a little hesitant to do what you need to do," Nagy said Saturday. "He's in a good spot. We'll get him right with his foot. Hopefully it's OK."