Morgan, an All-American player at Diamond Bar High in Southern California who was the first pick of the Portland Thorns in the NWSL draft, was injured when she collided with Jazmyne Avant of the Boston Breakers in the 10th minute of their game in Boston on Wednesday.
After Morgan was examined in the locker room, she returned to the Thorns' bench to watch the rest of the game, which Boston won, 2-1.
Morgan, 24, took to Twitter to thank fans for their support.
Despite the loss, Portland (10-6-4) will advance to the NWSL playoffs. Morgan leads the team with nine goals and four assists. FC Kansas City (11-4-5) was the regular-season leader, followed by Western New York (9-4-7), Portland and Sky Blue FC (10-6-4). Boston (7-7-6) finished fifth in the eight-team league.