Morrison hit 11 HRS at home last year, and 27 on the road. He has 98 PA's at Fenway with a .198 average, 5 HRS.
Moreland has a .287 avg. in Fenway, so Moreland for me. When you play 81 games at home, some batters have the swing to the Park they play in. 354 PA's is not a small sample either. Maybe Morrison can do it too, or better. But, why take that chance.
Also I think Moreland has a much more easier to Trade contract, if another team, has injuries. Not getting him for one year, if Traded this year, you get for next year too. Always like 2 year deals. Might get better Prospects with 2 year deals.
When you Trade Rentals, the guy your Trading, better be exceptional, to get good Prospects. Neither of these guys are, so contract might be important, to team your Trading too.