Nelson will be allowed to practice with the team and play in pre-season games but cannot play in the Bills' first four regular-season contests -- against Miami, Green Bay, the New England Patriots and New York Jets -- the league said.
The 6-foot-5 second-year player will be eligible to play in the Bills' game against the Jacksonville Jaguars Oct. 10.
Nelson caught 17 passes for 156 yards and a touchdown last season.
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