Morales is scheduled to undergo surgery today. He was leading the club in batting average (.290), home runs (11), total bases (94) and RBIs (39).
Morales connected with one out and circled the bases to a waiting celebration. He leaped toward home plate and landed awkwardly. He quickly went down and grimaced as he rolled onto his back.
"It'll change the way we celebrate," Angels manager Mike Scioscia said. "It sure was exciting, but you always wonder if it's an accident waiting to happen . . . It's definitely not the mood we would expect in the clubhouse after a win, but when something like that happens, it's definitely disturbing," he said.
Angels starting pitcher Jered Weaver, who was icing his arm while watching the situation unfold on television, said: "Anytime you have a walk-off hit, everybody celebrates at home plate. It was just a fluke thing."
Red Sox 1, Royals 0
Buchholz (7-3) allowed four hits - three singles - walked four and struck out four in posting his sixth win in seven starts. He's 3-0 with a 1.32 ERA in his last three outings.
The loss snapped the Royals' three-game winning streak.
Blue Jays 5, Orioles 2
Overbay hit a solo drive off newly promoted Chris Tillman in the second, ending an 0-for-17 slump. Overbay has six home runs this season and eight multihomer games in his career.
Aaron Hill also homered for Toronto, which leads the majors with 85 home runs. The Blue Jays have hit 50 homers in May, a team record for a single month.