Question On IR - DTR

Can the IR-DTR designation be used as late as Week or 5 or 6 to have a player available for the playoffs?

I believe it can be used at any point during the season, you're just risking wasting time if you use it later in the season and the player won't be ready anyways (aka later in the year smarter to use on a less serious injury where you know the player will return in the timeframe).