New York Jets quarterback Sam Darnold is "not a lock" to return in Week 5 against the Philadelphia Eagles.
The second-year quarterback, currently sidelined with mononucleosis, will undergo more testing on Monday, according to ESPN's Chris Mortensen:
Chris MortensenJets QB Sam Darnold still has hurdles to clear to play week 5. He says he will have more tests Monday on his spleen. If it's not as enlarged, he can begin practicing and working out. His cardio has been limited to walking & stationary bike. Not a lock but hopeful after mono bout
The 0-3 Jets have a bye in Week 4, and the team was hoping Darnold wouldn't be forced to miss any additional time with the illness, especially considering that a potential 0-4 start would be a major blow to the team's already fading postseason hopes.