On the bright side, it sounds like McDonagh’s issue is minor: the Rangers deem it a flu.
(Let’s assume this is actually the flu and not code for some other injury.)
After warming up briefly, McDonagh and the Rangers likely came to the conclusion that it wasn’t worth it tonight. With him out of the lineup, Adam Clendening returns to the Rangers’ defense corps.
That’s not necessarily an even trade, although some have been quite happy with Clendening’s work in a depth role this season.