What's confirmed: Warren entered the weekend listed as questionable with a groin injury, and the Colts moved Will Mallory back onto the 53-man roster Friday as cover at the position. Weekend reports had called Warren a game-time decision, so this is the downgrade fantasy managers were waiting on. He won't play Sunday.
What isn't known yet: the Colts haven't said how long the groin problem could linger. Nothing points to injured reserve or a longer absence. That could change once the team updates his status this week.
Warren isn't the only receiving option missing. Ashton Dulin is out as well, which leaves the Colts thin in the passing game. Expect Mallory to take most of the tight end snaps against Tennessee, with Alie Cox mixing in. On the outside, Josh Downs and Keenan Allen are the most likely to pick up the extra targets.
For RSO owners, the move is simple if Warren sits in your lineup: swap him out now, before the 1 p.m. lock. Pat Freiermuth is active for Pittsburgh at Tampa Bay if you have him on your bench. Mallory is worth a look as a one-week fill-in in deeper leagues, but don't hand him a multi-year contract off one start.
Don't treat this as a reason to sell Warren in dynasty. A one-game groin absence doesn't change his long-term outlook or what his contract is worth, and owners who panic today could hand you a discount. If you're shopping for a tight end, now is a decent time to ask about him.