New York Jets quarterback Sam Darnold will be sidelined indefinitely after being diagnosed with mononucleosis, coach Adam Gase announced Thursday.
Trevor Siemian will start Monday night against the Cleveland Browns.
Gase hinted that Darnold could miss several weeks. The coach suggested the earliest likely return as Week 5 at the Philadelphia Eagles, following the Jets' Week 4 bye. They play at the New England Patriots in Week 3.
"I don't want to put predictions on anything," Gase said, when asked about a specific timeline for Darnold's return.