"The goal is to be back against Philly in Week 5," Darnold said (h/t Ethan B. Greenberg of the Jets' official site). "That's what the doctors are estimating."
Darnold missed New York's 23-3 defeat to the Cleveland Browns after contracting mononucleosis.
He threw for 175 and a touchdown in the Jets' 17-16 Week 1 loss to the Buffalo Bills, revealing he was feeling under the weather at the time.
According to ESPN's Rich Cimini, doctors formally diagnosed him with mono last Wednesday, by which point he had already lost five pounds. The team effectively quarantined him in his apartment to ensure he wouldn't spread the disease.
The Jets' quarterback situation took another turn for the worse in Week 2 when Trevor Siemian suffered an ankle injury against the Browns. Jets head coach Adam Gase confirmed Siemian will have season-ending surgery to repair ligament damage in his left ankle.
That leaves Luke Falk as the starting quarterback for Sunday's game against the New England Patriots.
The schedule is favorable to New York in terms of Darnold's recovery because the team has a bye in Week 4. If he's back by Week 5, then he'll have only missed two games—not three.
Assuming they lose to the Patriots and fall to 0-3, the Jets are probably facing a lost season regardless of when Darnold is back. But his continued development can give fans something to get excited about as they look toward the rest of the year.