You should get the first one around day 58(if he's injured longer than that) and the 2nd one like a normal development cycle. If he's injured less than 60 days, he'll get one a day or two before he's fully recovered and the 2nd a day or two before he's eligible to come off the DL. If you don't need the player, there's no harm in leaving him on the DL. I usually take them off after they get a "regular season" development cycle. Unless I'm saving a spot on the 40(DL players do not count against the 40).