Either that, or they just wanted to get Hoyer some experience when he didn't know he was going to be coming in to the game. . . .
Heck, I honestly think that if Hoyer had somehow made it in for the TD, that we would have seen another botched two-pointer to end the game.
Or, more generally, Belichick was trying to decide what to do in terms of the playoffs (since he has some control over which teams get the wild cards), and was hedging his bets based on other teams' performances.
Another point, as someone noted: if the Patriots were seriously trying to win the game in the fourth quarter, why have Brace and Alexander in?