The unusual injury came on a hit some time in the first half of Thursday night's exhibition victory over the Detroit Lions. The Browns can't pinpoint exactly when the 6-foot-4, 240-pounder was hurt.
Mingo had been in The Cleveland Clinic since Thursday night. He was at the team's training facility Saturday and visited with defensive coordinator Ray Horton during the team's lunch break before practice.
"He looks great," Horton said. "As far as projections, the doctors will make that decision. We just want him to get healthy and are glad everything is OK. The projection will be whenever his body says he is ready to go."
The former LSU standout likely will be kept out of practice for the next week, and it's possible he will sit out Cleveland's final two preseason games at Indianapolis (Aug. 24) and Chicago (Aug. 29).
Horton isn't too worried about Mingo missing time.
"For a young guy, he needs every rep he can get," Horton said. "He is very smart. He is on page. For us, it's just reps. It's seeing a different look. It's seeing (Colts QB) Andrew Luck. It's seeing different fronts, what they have and how they want to block him. It will retard a little bit, but he is pretty gifted in what he does and he picks things up fast. How much? I can't give you a quantitative answer, but it will hurt him a little bit."
Mingo played only on the kickoff-coverage and punt-return teams against the Lions. On Friday, coach Rob Chudzinski said even after reviewing the game, the team did not see any major impact that could have caused the injury.
"We looked at the tape," Chudzinski said. "There wasn't a big hit that you could see. Obviously he had a number of plays with some contact, but it was hard to determine which hit it was."
Chudzinski said Mingo was having trouble breathing before he left the field and was taken to the hospital.
The No. 6 overall pick in April's NFL draft, the speedy Mingo has been primarily playing special teams and with Cleveland's second-string defense. However, Horton has been working Mingo into some of the Browns' pass-rushing packages to use his ability to pressure the quarterback from the edge.
Fortunately, the Browns have others who can fill in while Mingo recovers.
"We have a lot of players at a lot of positions who can play for us," Horton said. "Depth is a key for us. We have quality players at a lot of quality positions. A lot of people use the mantra, `Next man up.' We believe in that philosophy that it doesn't matter who the starters are, it is give me 11 guys who want to go out and play and can play.
"He is one of our 11, so will it hurt our team? Yeah, it will hurt our team because of our depth, but we will get him back soon and we will plug him right back in."
Mingo was one of five Browns players to suffer a significant injury in the 24-6 win over the Lions.
Running back Dion Lewis broke his left leg and is scheduled for surgery. It's not known how long Lewis will be sidelined, and Chudzinski said the team will wait until after the operation before deciding whether to put him on injured reserve.
Lewis, acquired in a March trade from Philadelphia, has been a pleasant addition for the Browns, who were hoping to use him as a change-of-pace with starter Trent Richardson. Lewis' injury will further test Cleveland's depth in the backfield since Montario Hardesty is expected to miss at least one month after undergoing arthroscopic knee surgery Thursday.
Starting right guard Jason Pinkston (high ankle sprain) left FirstEnergy Stadium in a walking boot and on crutches. Chudzinski said rookie Garrett Gilkey, a seventh-round pick, likely will move into the starting spot.