Sam Darnold has been ruled out indefinitely with mono.

The New York Jets will start Trevor Siemian at quarterback on Monday against the Cleveland Browns.

Darnold isn't expected to return before Week 5 at the Philadelphia Eagles.

"I don't want to put predictions on anything," Adam Gase said, when asked about a specific timeline for Darnold's return. "I'm just glad we've got the bye week when we do."