Almora ran full-tilt into the center-field wall in an attempt to catch a sharply hit fly ball off Austin Hays' bat. He briefly corralled the ball, but it was shaken loose after the collision.
The outfielder was down on the ground for a couple of minutes but exited the field under his own power. He may have avoided serious injury.
Almora later disputed the call on the field that it wasn't a catch.
After the game, manager Luis Rojas said Almora's X-rays on his shoulder and neck came back negative, according to Anthony DiComo of MLB.com. He'll undergo further tests Wednesday.