Injuries already taking toll on top 25

In this Aug. 31, 2014, file photo, Tennessee offensive lineman Marcus Jackson (75) provides pass protection during an NCAA college football game against Utah State in Knoxville, Tenn. Senior guard Marcus Jackson, the Vols’ most experienced offensive lineman, likely will miss the entire season with a biceps injury. (AP Photo/Knoxville News Sentinel, Michael Patrick, File)

KNOXVILLE, Tenn. (AP) — Tennessee has no time to celebrate its first Top 25 appearance in three years.

The 25th-ranked Volunteers are too busy adjusting their depth chart after three of their players suffered likely season-ending injuries in training camp.

Senior guard Marcus Jackson, the Vols' most experienced offensive lineman, likely will miss the entire season with a biceps injury. A similar injury has knocked out reserve guard Austin Sanders for the season.

Rashaan Gaulden, who had been working as Tennessee's first-team nickel back, also was lost for the season with a broken foot.

"It's unfortunate, but it's also a part of the game," said Tennessee coach Butch Jones, whose team is in the rankings for the first time since September 2012. "It's (going on) across the country."

Indeed, Tennessee isn't the only Top 25 program dealing with major injuries just before the start of the season.

Here's a look at some other players from Top 25 teams with potential season-ending injuries.

Notre Dame DB Shaun Crawford and DT Jarron Jones. Notre Dame's 2014 season came unraveled largely due to injuries that decimated its defense. Now the 11th-ranked Fighting Irish are losing defensive players even before the season has started. Jones, a returning starter who made 40 tackles last season, tore the medial collateral ligament in his right knee. The loss of Jones likely results in bigger roles for freshman Jerry Tillery and sophomore Daniel Cage. Crawford, a freshman competing for playing time at nickel back, tore his anterior cruciate ligament in practice.

Michigan State linebacker Ed Davis. This fifth-year senior injured his knee in an Aug. 12 practice for the fifth-ranked Spartans. Davis had 58 tackles — including 12 for loss — and seven sacks to earn honorable mention all-Big Ten honors last season. "It was very unfortunate," Michigan State coach Mark Dantonio said. "Things happen when people are running and cutting and things of that nature on the field. It just happened."

Oregon running back Thomas Tyner. After coming on strong during last season's College Football Playoff, Tyner has undergone offseason surgery on his left shoulder. Although the seventh-ranked Ducks don't announce injuries as a policy, players have indicated Tyner's return this season is doubtful. Tyner ran for 573 yards last season. He rushed for 124 yards and two touchdowns in a Rose Bowl victory over Florida State. Oregon still returns Royce Freeman, who rushed for 1,365 yards and 18 touchdowns last season.

Clemson linebacker Korrin Wiggins. No. 12 Clemson's young defense took a major hit when Wiggins tore an anterior cruciate ligament while trying to recover a fumble during an Aug. 12 scrimmage. Wiggins, who has played defensive back as well as linebacker, would have been one of only four returning players who started at least six games for a Clemson defense that allowed the fewest yards per game of any Football Bowl Subdivision team last season.

Arkansas running back Jonathan Williams. The 18th-ranked Razorbacks lost half of their dynamic duo at running back when Williams hurt his left foot during an Aug. 15 scrimmage. The injury will knock Williams out for the regular season, though Arkansas coach Bret Bielema has indicated there's a slight chance the senior could play in a bowl game. Williams rushed for 1,190 yards and 12 touchdowns last season after running for 900 yards in 2013. The Razorbacks still have Alex Collins, who has rushed for more than 1,000 yards in each of the past two seasons.

Arizona center Carter Wood. The offensive line figured to be one of the major issues facing No. 22 Arizona even before a chronic foot injury knocked Wood out for the season. Wood made his first career start in last season's Fiesta Bowl and was projected to open this season as the Wildcats' starting center. Arizona likely will move Cayman Bundage over from left guard to center.