Edsall said Tate, a senior and team captain, will seek a medical redshirt to return in 2012. Following surgery, he will be out six to nine months, according to the school.
Edsall would not disclose the nature of Tate's injury. "This is just something that he's had. He's just taken a hit in one of the games this year," the coach said.
Two people who know Tate describe a nagging injury that has required a procedure to drain a buildup of fluid. Maryland wouldn't say whether it was a leg injury. Tate, whose right leg has been wrapped, last played against Towson on Oct. 1, recording nine tackles. He warmed up before the Georgia Tech game on Oct. 8 but did not play.
On Saturday, Tate walked to midfield with two other captains before Maryland's 41-16 loss to Florida State, but he was not wearing pads.
Tate has not been made available recently for media interviews. Maryland quoted the player in a release Sunday saying of the surgery: "This is the best course of action to get healthy and get back on the field next season."
Last season, Tate, a solid NFL prospect at 6 feet 4 inches and 220 pounds, had 100 tackles and 3.5 sacks as a safety. His 7.7 tackles per game were seventh in the Atlantic Coast Conference.
Tate was switched by Edsall in the offseason to a hybrid linebacker-safety position called "Star."
Edsall was also asked during his Sunday media conference call about Maryland's uncertain quarterback situation.
Maryland starter C.J. Brown left Saturday's game after Florida State linebacker Nigel Bradham delivered a blow to Brown's head in the third quarter. "I tried to slide but didn't get all the way down," Brown said. "The guy came up and drove me in the head."
Maryland usually makes the starting quarterback available for interviews after games. It was uncertain after the Florida State game which quarterback would appear. Both showed up.
O'Brien (9-of-18, 180 yards, one touchdown passing and one running) entered the interview room at Doak Campbell Stadium wearing a black sweatsuit with a pair of headphones dangling around his neck.
"It felt good to get out there sweating again," he said. "We kind of knew we were going to have to air it out a little bit to have a chance of winning."
After Brown replaced him — first during the Georgia Tech game and then as the starter against Clemson on Oct. 15 — O'Brien said he believed he would get another opportunity. "I felt like I was going to. Obviously you don't want to get back in there because he gets hurt. That's the last thing you want," O'Brien said.
"Me and [Brown] are really tight. People may not know that," O'Brien said. "We're really good friends off the field and we realize we have two good quarterbacks here and only one can play. When he's in there, I'm in his ear with what I see on the sideline, and vice-versa. It's hard to describe to someone because it's kind of a weird relationship. But it's good."
It is unclear whether Edsall would have turned to O'Brien even if Brown was not forced from the game. Brown said he was medically evaluated in the locker room and cleared to return. But Edsall stuck with O'Brien, who led Maryland to a touchdown on his second possession.
The big question is who will start when the Terps (2-5, 1-3 ACC) try to snap a three-game losing streak against Boston College on Saturday at Byrd Stadium. Edsall said he anticipates a game-time decision.
"I expect to start every week," O'Brien said. "I feel like I can start, and I know C.J. feels the same way. I feel like the offense didn't miss a beat when I got in."