Report: Darnold to undergo more tests Monday, uncertain for Week 5

New York Jets quarterback Sam Darnold isn't a lock to be cleared for next Sunday's game against the Philadelphia Eagles despite optimism regarding a Week 5 return, according to ESPN's Chris Mortensen.

Darnold still has to clear hurdles before returning from mononucleosis, as Mortensen notes, and he'll undergo more spleen tests on Monday. If his spleen isn't as enlarged, the young passer can begin practicing and working out.

The 2018 first-round pick hasn't been cleared to run, and his cardio has been limited to walking and the stationary bike.

Darnold, who has missed the last two games, said he wasn't feeling 100% during the Jets' season opener and his body "decided to shut down" following the contest. The 22-year-old also said he's lost only two pounds while battling the illness.

New York is on a Week 4 bye before visiting Philadelphia.