Tom Brady must appeal Monday, or sit New England Patriots' first 4

Tom Brady and the National Football League Players' Association have until Monday to file a response to the U.S. Court of Appeals for the Second Circuit's decision to reinstate the New England Patriots quarterback's four-game suspension.

Brady's team of lawyers, which now includes the 75-year-old Theodore B. Olson -- a U.S. solicitor general under former President George W. Bush who has argued before the Supreme Court 62 times -- will likely file for an "en banc" hearing before Monday's deadline, the Boston Globe reports.

That filing would allow all 13 of the active Second Circuit judges to decide whether or not an appeal of their ruling should be heard.

The NFLPA could also file for a panel hearing, in which the three Second Circuit judges that decided to reinstate Brady's suspension would rehear the case, according to the Globe.

Brady was suspended by NFL commissioner Roger Goodell on May 11, 2015, for his involvement in the Patriots' alleged deflation of footballs during the 2015 AFC Championship Game against the Indianapolis Colts, which New England won 45-7.

The suspension was overturned on Sept. 3, 2015, by U.S. District Court Judge Richard M. Berman, but was reinstated on April 25 by the Second Circuit judges.

Brady played in all 16 regular season games in 2015, leading the Patriots to a 12-4 record and another AFC title game appearance.

If Brady's suspension is again upheld, he would miss New England's first four games in 2016 against the Arizona Cardinals, Miami Dolphins, Houston Texans and Buffalo Bills.

He would be eligible to return on Oct. 16 against the Cleveland Browns.