This isn't unexpected...Mike Napoli caught all of tonight's extra inning game, and the team will be catching a late flight tonight to Detroit. Between the travel and there being four straight games (after Sunday's rainout), this seems like the perfect game to get Napoli a half-day off by letting him DH.
Moreland, meanwhile, had a brutal game today, with 3 Ks, a rally-killing inning-ending bases loaded GIDP, and an error. He's struggled throughout the playoffs, and if Torrealba hits tomorrow, we may see Torrealba stay in the lineup at DH going forward.