The San Francisco 49ers have announced that wide receiver Pierre Garçon has officially been placed on injured reserve.

Garçon left the 49ers' Week 8 road game against the Philadelphia Eagles with an apparent neck injury. He felt confident after the game that the injury was not a serious one. However, Garçon was not able to practice on Wednesday, which prompted the 49ers medical staff to send the receiver for more testing that night. The results showed a non-displaced fracture of the right C5 pedicle.

The injury, which is going to require about eight weeks of recovery, forced the 49ers to place Garçon on injured reserve and ending his season.

"They have to immobilize it," 49ers general manager John Lynch said on KNBR Thursday night as he broke the news. "Unfortunately, a guy who's been one of our, if not our best, players this season is out."

Garçon was acquired via free agency in March after signing a five-year, $47 million contract. Through eight games, he leads the 49ers with 40 receptions for 500 yards. Garçon, a 10-year veteran, spent his previous five seasons with the Washington Redskins and the four before that with the Indianapolis Colts. He was on pace for his third career 1,000-yard season. Until this year, Garçon had never played in fewer than 10 games in a season over his career.

"It's something we've got to deal with," 49ers head coach Kyle Shanahan said on KNBR Friday morning. "It was pretty hard to hear. Spent the night pretty upset about it. Woke up the next morning and it's time to move on. You've got to deal with it, embrace it, and someone's got to step up, and we've got to work to help everyone else out because we're not going to find a guy to replace Pierre."

Gilliam, who started at right tackle against the Eagles in place of Trent Brown, suffered a knee injury in the second quarter and was ruled out. He got the start because Brown suffered a concussion during a Week 7 matchup against the Dallas Cowboys and was not cleared in time to play against Philadelphia.

On April 17, Gilliam, who was a restricted free agent at the time, was signed by the 49ers to a one-year contract worth $2.2 million with $1.4 million guaranteed. In his three seasons before joining San Francisco, the tackle played in 44 regular season games for the Seattle Seahawks while starting 30.

Gilliam turned down lengthier contracts offered by the 49ers because he had hoped to become an unrestricted free agent following the season.