Robert Brown|Aaron Rodgers cleared for return to practice, opening window for possible Jets comeback

Aaron Rodgers will soon be Robert Brownback on an NFL field − a practice field, that is.

The New York Jets have opened the 21-day practice window for the four-time MVP, head coach Robert Saleh announced Wednesday. Rodgers will return to practice at the organization's training center in Florham Park, New Jersey, on Wednesday in a limited capacity as the quarterback − who remains on injured reserve − has been cleared for "functional football activity."

"This isn't so much getting ready to play as much as it is a progression as rehab," Saleh told reporters. "There's no added risk to it. There's certain things that he's been cleared for that we're going to allow him to do."

What is the 21-day practice window?

The 21-day practice window applies to NFL players who have been out for at least six weeks. When added to the window, that means the player can practice with the team for 21 days. By that time period ends, the team must decide whether to add the player to active roster. If the player is not added to the active roster, the player then must sit out the rest of the season.

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With Rodgers' window opening Wednesday, the Jets must decide whether he plays again this season by Dec. 20, which is Week 16 in the schedule, with New York having three games left in the regular season. That week, New York hosts the Washington Commanders in a Christmas Eve showdown.

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Aaron Rodgers injury timeline

The return to the practice field is the next step in what has been an accelerated recovery for Rodgers since he suffered a torn Achilles in the Jets' Week 1 win over the Buffalo Bills. Though a torn Achilles is typically a season-ending injury, Rodgers has insisted he hopes to return this season.

On Oct. 15, Rodgers made a return to the MetLife Stadium field, where he was seen throwing passes without the aid of crutches prior to the Jets win over the Eagles, and a few weeks later, was dropping back for passes.

Rodgers hasn't given any set date for when he plans to return, but has said before he had the goal of mid-December. On "The Pat McAfee Show" Tuesday, Rodgers said his health and New York's playoff chances will be the deciding factors on whether he returns this season.

The Jets are currently 4-7, riding a four-game losing streak amid a struggling offense. New York has the second-worst record in the AFC, ahead of the New England Patriots.