Safeties Danny McCray and Barry Church and cornerback Orlando Scandrick are on the list filed Thursday, as well as retired safety Gerald Sensabaugh; former cornerback Michael Jenkins, now with the Oakland Raiders; and fullback Lawrence Vickers, who was released by the Cowboys last week.
Brent is charged in a Dec. 8 car crash that killed practice squad player Jerry Brown. Authorities say Brent's blood-alcohol level was twice the legal limit on the night of the crash.
His trial is slated to begin Sept. 23, the day after the Cowboys play the St. Louis Rams.
Heath Harris, the first assistant Dallas County district attorney, said Friday after being asked about the possibility of a plea bargain that he expects the case to go to trial.
"We're ready to go to trial, to let the citizens of Dallas County decide how strict our intoxication laws are going to be," Harris said.
George Milner, Brent's attorney, said Friday that he expected the six current and former Cowboys may be called to testify about being at the same nightclub as Brent and Brown the night of the crash.
A team spokesman did not immediately return a message seeking comment.
Brown's mother, Stacey Jackson, and grandmother Theresa Clark are listed as possible witnesses. Dozens of police officers and firefighters from the Dallas suburb of Irving, where the crash occurred, as well as officials from the Texas Alcoholic Beverage Commission could also be called.
State District Judge Robert Burns on Friday told attorneys on both sides that he was concerned about the massive media attention Brent's case has received. He asked all lawyers to be careful in their public comments, but did not issue a gag order.
Milner asked Brent to step in shortly after Dallas County District Attorney Craig Watkins was interviewed last month on KRLD-FM, "The Fan," during which he said Brent "still uses alcohol and illicit drugs."
"A person lost his life here," Watkins said on air. "Mr. Brent, based on the tests that we've seen, still uses alcohol and illicit drugs. And so for us to protect the public and send a message, we feel that we have a responsibility to make sure that he loses his freedom."
Brent has tested positive twice for marijuana since his arrest, but prosecutors have not shown proof in court that Brent has had alcohol. His ankle monitor for alcohol went off four times in February and March, but both sides agreed during a May court hearing that it was caused by the presence of alcohol in the air or near Brent.
"There is no evidence that the defendant drank any alcohol" based on that hearing, Burns said. "There's no evidence of that."
Milner said his request to Burns was mainly out of wanting to "preserve the integrity of the judicial system."