The University of Miami has lost its second starter on defense in a week, an especially unsettling situation as the Hurricanes get ready for No. 21 Virginia Tech on Saturday in Blacksburg, Va.

Defensive tackle Marcus Forston, a fourth-year junior, “suffered a noncontact knee injury during practice [Wednesday],” according to the Hurricanes’ sports information office, “and will be out for the remainder of the season.”

UM did not elaborate on the type of injury or if it would require surgery, but UM coach Al Golden told WAXY 790 late Thursday afternoon that Forston would need three months to recover.

“Brutal. I feel bad for the young man,” Golden told Dan Le Batard. “That’s a position we’ve just been crushed at. Luther Robinson has been out so far for every game. Curtis Porter has been out for every game. Now Marcus is out. It’s been brutal in there at defensive tackle. He’ll come back and be fine. Right now we need the next young man to step up and play better for us.”

Another defensive starter, outside linebacker Ramon Buchanan, sustained a noncontact, season-ending knee injury during the Bethune-Cookman game last Saturday.

Shortly after UM reported Forston’s injury, it released more unexpected news. Defensive tackle Robinson and highly recruited freshman defensive end/tackle Jalen Grimble will miss the game Saturday with “lower extremity” injuries.

Miami’s weakest part of its game, by far, has been its rushing defense, and these latest injuries are crushing blows. UM is ranked 105th nationally in rushing defense of 120 teams in the Football Bowl Subdivision.

The Hurricanes are allowing 202.2 ground yards per game and about to face a team with the seventh-ranked running back in David Wilson.

Forston, 6-3 and 300 pounds, had five tackles and a sack this season in three games started. Last year, Forston started 12 games and had 37 tackles, six sacks and 12 tackles for loss. But he tore the medial collateral ligament of his right knee early in spring practice, and underwent knee surgery.

He had finally recuperated fully and was trying to regain steam on a team that woefully needs help among its front seven. UM also recently announced the season-ending loss of defensive tackle Porter, who appeared to have a hand/finger injury.

Micanor Regis, a senior, is the lone starting veteran defensive tackle. Junior college transfer Darius Smith — 6-2, 360 pounds and nicknamed “the plug” — could replace Forston, as could former defensive end Adewale Ojomo.

Ojomo, a junior, was converted into a defensive tackle just last week. A fiery player, Ojomo is 6-4 and 265 pounds — tall but considered undersized for the interior.

“If he wasn’t strong, we couldn’t do it,” Golden said of Ojomo’s switch. “He has a physical presence. What he doesn’t have in girth, so to speak, he has in an excellent first step.”

Forston came from the heralded Miami Northwestern High 2008 recruiting class that included quarterback Jacory Harris and linebacker Sean Spence. He has faced his share of adversity at Miami. He was one of eight players suspended by the NCAA before the season, sitting out the opener at Maryland for receiving impermissible benefits worth approximately $400 from former UM booster Nevin Shapiro.

Forston was seen as a team leader and badly wanted to help the Hurricanes overcome a rough period.

“I feel like me as a leader, I have to bring energy every day,” he said in late August. “I’ve got guys looking at me. [I can’t have them saying], ‘Marcus is having a down day.’ There are a lot of young guys on that defensive line. Even if I’m having a bad day, I can’t show it.”

As a freshman in 2008, he played in 12 games and had 18 tackles, nine quarterback pressures, three sacks and 4.5 tackles-for-loss — and was subsequently named a freshman All-American.

He played in the first three games of 2009 but was plagued with injuries and eventually underwent shoulder surgery.

On Saturday, the Canes will get back safety Ray-Ray Armstrong, one of the eight suspended players. The last remaining suspended player, defensive end Olivier Vernon, will return for the Georgia Tech game Oct. 22.