The New York Jets are going to be without their starting quarterback for several weeks.
Jets coach Adam Gase announced Thursday the second-year QB has mononucleosis and will miss at least the team's NFL game against the Cleveland Browns on Monday night.
Trevor Siemian will start in Darnold's place, and could be the starter moving forward until Darnold recovers.
The Jets have a game at New England in Week 3 before they have a bye-week break, and then games at Philadelphia, at home against Dallas and New England before a road game at Jacksonville on Oct. 27 to cap a rough opening stretch.
Darnold was sent home by the team Wednesday.
Gase says Darnold's biggest concern is weight loss, and adds Darnold has already lost about five pounds.