The team announced Tuesday that Bryant suffered a concussion in Monday's practice and will not play Thursday against the Seattle Seahawks. The Cowboys have not played their starters in a preseason finale in years, which means Bryant's next appearance could be the Sept. 11 season opener against the New York Giants.
On Tuesday coach Jason Garrett said Bryant "is much better today."
Garrett said that Bryant was hurt when the receiver's head hit the shoulder pads of safety Barry Church.
"Somehow the angle of Barry's shoulder pads and the angle of Dez's head, they hit," Garrett said, "Dez took a couple of steps and felt something. We obviously took him out for the rest of practice."
Because the concussion happened so close to Thursday's kickoff, Bryant was immediately ruled out. Garrett was not sure whether Bryant or defensive tackle Tyrone Crawford, who suffered a concussion and has been ruled out as well, would make the trip to Seattle on Wednesday.
The Cowboys' next full practice is scheduled for Saturday.
"We don't think there's any long-term concern here," Garrett said.
Bryant took to Twitter Tuesday to tell Cowboys fans not to worry.
In two preseason games, Bryant has four catches for 74 yards and two touchdowns, as he returns from a broken foot that required two surgeries and limited him to nine games last year.
Bryant has had a productive training camp after being limited in his offseason work following a bone graft surgery in January.
As the Cowboys left Oxnard, California, he said it was the best training camp he has had in his career. He was given one day off in camp to rest.
"My mind is right," Bryant said last week. "My confidence is sky-high right now. I think it's the best it's ever been."
Bryant caught a career-low 31 passes for 401 yards and three touchdowns last season. He missed five games after undergoing surgery after breaking the fifth metatarsal in his right foot the day after the season opener. He hurt his knee in his second game back and struggled to make an impact as the Cowboys suffered from substandard quarterback play.
Once the Cowboys were eliminated from playoff contention, Bryant was inactive and eventually placed on injured reserve.