If the Tigers were to trade Porcello to the Angels for either Bourjos or less likely, Trumbo, I would prefer the latter b/c of his PH ability off the bench in inter-league games. But both Ajax and Dirks spent time on the DL last season, so Trumbo's defense would be suspect in the OF, IF one of the two again or maybe Hunter were to be injured and go on the DL next season. The Angels obviously do not need another OFer, so the Tigers could not include Brennan in a trade. Boesch by himself won't fetch much, and I think that the best way to increase his value slightly is to include him in a trade with Porcello or maybe Peralta, IF the Tigers were to trade Kid Rick for a better fielding but perhaps offensively limited SS.
At any rate it is obviously impossible to predict where the Tigers might need temporary help on the field or on the mound due to injuries. Both Scherzer and Fister were injured for awhile last season, and it would suck if the Tigers traded Porcello, only to lose two SP to the DL ~the same time, much less one at a time.
Tigers are also counting on increased offensive production from both Hunter and the returning VMart. But one or both could possibly have down seasons @ the plate, and one or more of Avila, Peralta, AJax, Prince, and/or Dirks could experience lower offensive production as well.