Packers receiver Javon Walker injured his right knee in the third quarter against Detroit on Sunday and will miss the rest of the season, the Packers announced Monday. "It was his ACL," Packers coach Mike Sherman said after the Lions won 17-3. A torn ACL requires reconstructive surgery and anywhere from six to 12 months of rehabilitiation. "Guys have to step up and replace a very high quality player," Sherman told the Milwaukee Journal Sentinel. "I doubt he'll be back any time in the near future." With Walker injured, the Journal Sentinel is reporting that Donald Driver will move from split end to flanker, Walker's position, and Robert Ferguson will start at split end.