Maryland Coach Randy Edsall said that senior left guard Andrew Gonnella remained in Atlanta on Sunday after undergoing suffering what the coach characterized as a “very serious knee operation injury.” Gonnella, one of four team co-captains, suffered the season-ending injury in the fourth quarter of Saturday’s 21-16 loss at Georgia Tech.

Edsall said Gonnella, one of four team co-captains, is expected to return to Maryland on Monday and will undergo another surgery at an undisclosed time. Edsall said he spoke to Gonnella on Saturday night and Sunday morning.

“He is doing well,” Edsall said. “We just look forward to having him back here with us on Monday.”

Edsall also said to expect a game-day decision on who will be the starting quarterback against Clemson on Saturday.

Danny O’Brien, last season’s ACC rookie of the year, was replaced by C.J. Brown in the second quarter Saturday after O’Brien completed 1 of 6 passes and threw one interception. Brown displayed mobility — 77 of his 124 rushing yards came on a fourth-quarter touchdown run — but he also struggled in the passing game. Brown completed 4 of 17 passes for 36 yards and threw one interception.

“We’re going to evaluate that situation just like we evaluate all the positions on a week-to-week basis,” Edsall said.

In a tweet Sunday afternoon, Edsall thanked Georgia Tech Coach Paul Johnson for visiting Gonnella in the hospital Sunday.

Edsall said he did not wish to elaborate on the injury out of respect for Gonnella and because of privacy laws.

After suffering the injury, Gonnella remained on the ground nearly 15 minutes, flanked by teammates, medical staff, Edsall and Athletic Director Kevin Anderson, before he was placed in an ambulance and taken to Grady Medical Center.

The injury to one of their team leaders left players emotionally shaken after the game.

Sophomore Pete White is expected to be the leading candidate to replace Gonnella in the starting lineup.

Edsall singled out defensive tackle Joe Vellano for playing a substantial role in helping the Terrapins hold Georgia Tech’s vaunted triple-option offense to 30 points under its season average. The junior Vellano finished with 20 tackles.

“We had probably one of the most outstanding performances that I think — I know — I have ever seen out of a defensive lineman,” Edsall said. “When you watch the film, and you watch how hard he played, he just did a phenomenal job. The opposing coaches were seeking him out after the game because Joe was very, very disruptive. He just was relentless all day long.”