J.T. Miller skated on Thursday morning, but Ryan Callahan did not. Both are working their way back from injuries.Miller, however, skated as a defenseman. No, he's not changing his position. Miller skated with D Mikhail Sergachev to even out the numbers with 13 forwards and seven defensemen skating."We're hopeful for the trip," coach Jon Cooper said. "He's getting close. He's making strides."Miller has missed six games with an undisclosed upper-body injury. The upcoming trip features a back-to-back against Buffalo and the Islanders on Saturday and Sunday, then a game against Dallas on Tuesday.Callahan missed Tuesday's game with an undisclosed upper-body injury. He skated in the optional morning skate before the game, but wasn't in the lineup.Cooper said he "re-aggravated something," which presumably means either the shoulder or back spasms that have kept Callahan out of games this season. Cooper expects Callahan to be back during the trip.