FILE- In this May 9, 2014, file photo, Buffalo Bills first-round draft pick Sammy Watkins, right, poses for photos with general manager Doug Whaley at Ralph Wilson Stadium in Orchard Park, N.Y. Whaley's swing-for-the-fences philosophy is evident in the new-look offense the Bills will unveil Sunday, when they open training camp in suburban Rochester. There's rookie receiver Sammy Watkins, who was drafted fourth overall after Whaley traded Buffalo's 2015 first-round pick to Cleveland. (AP Photo/Bill Wippert, File)
PITTSFORD, New York — Some two weeks later, Bills general manager Doug Whaley can still recall being surprised after he learned starting linebacker Kiko Alonso had sustained a season-ending knee injury.
"Absolutely it was a shock," Whaley said Friday, when Bills veterans began reporting for the start of training camp in suburban Rochester. "It's nothing you want to hear on vacation."
Well, vacation's over for Whaley and the Bills, who will hold their first practice on Sunday. They will be spending much of the next seven weeks attempting to fill a big hole at outside linebacker after Alonso tore a ligament in his left knee while working out in Oregon on July 1.
And the Bills have an additional concern at left tackle, with starter Cordy Glenn sidelined by an illness. Without revealing the nature of the illness, Whaley said the team is awaiting test results to determine how much time Glenn could miss.
Glenn, who has been placed on the active/non-football illness list, will be limited to light exercises on the sideline until being cleared by team doctors.
For now, replacing Alonso is the team's most pressing need.
"It's a tremendous loss, but no one's crying for us," Whaley said. "It's next man up. And we think we've built a roster that can sustain a loss like this. But our expectations aren't going to drop."
It won't be easy for the Bills to find someone capable of replacing Alonso, an NFL rookie of the year contender last season. The second-round draft pick led Buffalo with 159 tackles, two fumble recoveries and tied for the team lead with four interceptions while not missing a defensive snap in 16 games.
Alonso had what Whaley described as successful surgery on Thursday. He'll spend the next month recuperating at home before starting rehab at the Bills facility in Orchard Park.
The initial plan, Whaley said, is to have a three-way competition between rookie third-round draft pick Preston Brown, third-year player Nigel Bradham and second-year player Ty Powell.
It helps that all three had opportunities to work with the starting unit during the spring practices. They were filling in for Alonso, who practiced on a limited basis while recovering from offseason hip surgery.
Brown played mostly inside linebacker at Louisville but, at 6-foot-1 and 255 pounds, has the size and range to play the outside spot. Bradham has 13 starts in 32 games since the Bills drafted him in the fourth round in 2012. Powell appeared in five games last season after the Bills signed him off the New York Giants practice squad in October.
In providing other injury updates, Whaley said the Bills placed starting cornerback Leodis McKelvin on the active/physically unable to perform list to ease him into training camp. McKelvin had offseason hip surgery.
Reserve defensive tackle Alan Branch was placed on the active/non-football illness list because of an issue that came up while taking his physical. Whaley would only say the test results are being examined to determine when Branch can begin practicing.
NOTES: The Bills have two holes to fill after releasing WR Cordell Roberson and DB Darius Robinson on Friday. Whaley said he expects to fill the roster spots on Saturday. ... Bills rookies reported for training camp on Wednesday. Buffalo will be the NFL's first team to open camp on Sunday. ...The Bills are starting early because they open the preseason playing the Giants in the annual Hall of Fame Game in Canton, Ohio, on Aug. 3.