Byrd, who was initially diagnosed with a plantar fasciitis injury, is currently a doubt to start his side's opening match of the regular season against the New England Patriots on Sunday, having only taken part in limited practice on Sunday.
Coach Doug Marrone refused to elaborate on whether the 26-year-old would be available for the match, but Byrd was quoted as saying that he was doing everything in his power to return in time.
"Byrd: Has been getting plantar fasciitis examined for second opinion. Working 'as much as my body can endure' to get back in lineup," read a tweet from the team's official Twitter account.
Meanwhile, the Bills have welcomed back CJ Spiller after the running back had missed the last week of practice due to personal reasons.