After Maicer Izturis singled, Bobby Abreu was intentionally walked and Reggie Willits reached on an error. Morales then unloaded off Brandon League (4-5), sending the ball over the left centerfield wall to give the Angels their third win in four games.
Morales, however, injured his left leg in the home plate celebration that followed the blast. His leg as put in an air cast and he was taken off the field on a stretcher, only a few innings after Angels slugger Torii Hunter was removed from the game after being hit in the hand by a pitch.
X-rays revealed no broken bones in Hunter's hand, ESPN.com reported.
Brian Fuentes (3-1) was credited with the victory after pitching a perfect top of the 10th, while starter Jarrod Weaver didn't allow an earned run in seven innings of work.
Seattle starter Felix Hernandez was brilliant, holding the Angels to one run on six hits over eight innings.