I checked the wiki, and there's no record of Sam Darnold being injured on a hit from Dre Greenlaw on the sideline. Darnold's only documented 2026 injury is the soft-tissue glute/hip issue he suffered in Week 1 vs. New England (he was ruled out for Week 2, with no IR plans and an expected ~4-week timetable) (from the Sam Darnold page).
What the wiki does have on Greenlaw's sideline behavior: in Week 5 he was suspended one game for headbutting Seahawks LB Ernest Jones IV after a sideline confrontation — not Darnold (from the Dre Greenlaw page). If this Darnold hit happened, it's not in the wiki yet. It may be breaking news that hasn't been logged — happy to re-check later if you want.