BEREA, Ohio -- The Browns' worst fears were confirmed Monday when they received news that two-time Pro Bowl center Alex Mack and defensive end Armonty Bryant will both need surgery and be lost for extended time from serious injuries in Sunday's 31-10 rout of the Steelers.

"I told the team in the meeting today, we lost two warriors in (Mack) and Armonty,'' said coach Mike Pettine. "But we'll check the mail and there's not going to be any sympathy cards from around the league.''

Bryant suffered two torn ligaments in his right knee -- an ACL and an MCL according to a source -- and will undergo season-ending surgery later this month. Mack broke his left fibula and possibly suffered ligament damage in his ankle. If it's just the broken bone, Mack could possibly make it back after 8-10 weeks Pettine said.

But if there's ligament damage, Mack will also be lost for the year. He'll undergo surgery in a few days -- possibly with Dr. Robert Anderson in North Carolina -- and they'll know more about his timeframe after that. Dr. Bert Mandelbaum, an orthopedic surgeon and co-chair of medical affairs at Institute for Sports Sciences in Los Angeles who has not treated Mack, said surgery to repair ligaments and a significant break could take four two six months to heal.

"It's the cliche, but it is truly next man up,'' said Pettine. "We can't feel sorry for ourselves and I'm confident that we'll put a functional group out there."

The source said Bryant's recovery will take about six to nine months after the surgery, which should put him back on the field somewhere between the beginning of organized team activities in May and training camp in August. Pettine said the Browns are working on signing a defensive lineman with so many of them injured right now. As it was, Bryant was starting for Phil Taylor, who underwent a minor knee scope last week and will miss several games.

"It'll be difficult to replace (Bryant),'' said Pettine. "He was one of our most productive pass rushers, and in the short amount of time he was in there yesterday, he was playing well.''

Desmond Bryant, who played 77% of the snaps on a shorthanded line, lamented Bryant's loss.

"It's tough for him to be out,'' Bryant said. "He's been doing a great job for us this year, especially in the passing game like we all knew he could do, but even in the run game. Yesterday, he only played six plays, but he already had two tackles. It's great to see his development. It's been really great. I'll be praying for him. I hope for a speedy, great recovery. But until then, unfortunately it's the nature of the business, we've got to keep moving."

Desmond Bryant can relate to Bryant's injury, because he missed the last four games with an irregular heartbeat last year and didn't know if he'd make it back.

"I was in the same position last year,'' he said. "I know the pain it is watching from at home, especially away games. But you've just got to keep your head up and keep working."

Pettine re-interated that the impact of Mack's loss is more than his ability to dominate in the middle of the line on a week-to-week basis.

"It's tough,'' said Pettine. "It's not just losing his play, but it's also an emotional letdown as well. To have a guy that just exemplified everything you're trying to get done, to lose him. And potentially, we still don't know, but it's looking like....it is for the year. It's big.''

The Browns are exploring their options to replace Mack, but will likely head into Jacksonville Sunday -- against the winless Jaguars -- with the same crew they had against the Steelers after Mack went down in the second quarter. Greco moved over from right guard and journeyman Paul McQuistan came in off the bench to replace Greco.

"John Greco did an outstanding job of stepping up and playing center and then Paul McQuistan coming in and being able to finish the game out for us at guard, I thought that was critical to our success,'' said Pettine.

The Browns also have third-year guard/center Nick McDonald set to come off the non-football injury list any day with his wrist injury. Claimed on waivers July 22 despite the injury, McDonald, originally signed by the Packers as an undrafted free agent out of Grand Valley State in 2010, started two games for the Patriots at center in 2011, and one at right guard 2012.

"In Nick McDonald, we have a guy that's played some quality snaps at center before in the league,'' said Pettine. "He's just coming off NFI. The plan right now is to practice him this week, but I don't foresee him playing this week. I could see in the short term that's going to be John. But we're a mile away from making that decision. We have some options whether we keep Paul at guard, whether we let Paul continue to be the swing and have (Vinston) Painter to play guard.''

Painter (6-4, 310) was originally drafted by the Broncos in the sixth round of the 2013 draft out of Virginia Tech. The Browns signed him last month off the Broncos' practice squad. In addition, the Browns have three linemen on their practice squad that can be called up.

"There's options,'' Pettine said. "That's stuff that I'm going to get with the offensive guys tonight, and we'll start to work out."

Pettine was moved by the sight of his entire team spilling out onto the field to wish Mack well when he was on the cart, the aircast protecting the broken leg. The ironman -- all 5,279 straight snaps of him -- smiled and laughed in the face of great pain and showed his teammates once again how tough he really is.

"That was the great part about that (team greeting), it was spontaneous,'' said Pettine. "But that shows you what the guys think of Alex and what he meant to this team and they say a guy who was a warrior for us. He goes full speed in practice.''

Pettine described a scene on a deep pass in Tennessee, where Mack "took off like the ball was thrown to him and he's like that in practice, too. I think that he sets a great example and when your best players are your hardest workers you've got a chance to be something special."

Greco, who lost 25 pounds coming into this season to help him run the zone-blocking scheme, is up for playing center for as long as they want him to.

"Hopefully I showed enough to where they're good and confident with me there,'' he said. "But that's ultimately someone else's decision.''

He noted that the players dedicated the game to Mack and Bryant after they left.

"You want to do it for those guys,'' said Greco. "Armonty, in particular, has been having a heckuva year and he started off the game great. And on our side, we'll be playing for Alex as long as he's out. But everything we accomplish this year or don't, he's right there along with us. He's been in this thing long enough to where we're including him in everything.''