The NFL had put together a schedule for the use of replacement referees through the first five weeks of the season, according to ESPN's Adam Schefter.
NFL.com reported that the NFL officially scheduled replacement officials through Week 3 and has tentatively scheduled replacement referees through "at least" Week 5, according to an NFL official.
The move suggests the NFL does not believe a resolution of its contract dispute with the locked-out regular referees is imminent.
The league and the NFL Referees Association have been unable to reach an agreement on several issues, including salary, retirement benefits and operational issues.
The number of penalties called in the first week of regular-season games was not much different from the average over the past four years.
However, there have been some complaints, notably by the Bills' Mario Williams, who criticized the replacement refs for not calling what he claimed were numerous illegal hands to the face infractions by New York Jets right tackle Austin Howard.