Mexico captain Edson Álvarez will undergo tests in the next couple of days after being forced off with an injury in the first half of his team's Copa América win over Jamaica on Saturday at Houston's NRG Stadium.
After sprinting back during a counter attack from Jamaica, the West Ham midfielder suddenly hit the ground in pain, clutching his left hamstring.
Álvarez had to be helped off the field in obvious pain and was visibly distraught at his match and potentially his tournament coming to an end after less than 30 minutes.
"With Edson, we're going to wait a couple of days to give him an examination and know well what he has," Mexico manager Jaime "Jimmy" Lozano said in a postgame press conference. "Obviously as it is with any other player, the intention is not to risk anything. He felt something in his leg."
In both teams' opening game of the competition, Michail Antonio appeared to put Jamaica ahead with a short-range header in the 50th minute but the goal was disallowed for offside following a video review.
Mexico went on to secure a 1-0 victory, courtesy of Gerardo Arteaga's 69th-minute strike from the edge of the penalty area.
"It's not easy to recover and remain balanced after your captain exits so rapidly ... but it seems to me that the team stabilized quickly," Lozano added.
Speaking on Friday, Álvarez stated that he had "goosebumps" at the thought of captaining Mexico for the first time at a major tournament.
Álvarez is a key experienced figure in a young Mexico squad undergoing a generational change under Lozano at the Copa América. Since his debut with Mexico in February 2017, only Jesús Gallardo has played more games for El Tri than Álvarez's 80.
He has also played more minutes for Mexico than any other player since Lozano took charge last year.
Mexico will next play Venezuela -- who beat Ecuador 2-1 in the day's other Group B match -- at Inglewood, California, on Wednesday. The group finishes on June 30, when Mexico plays Ecuador at Glendale, Arizona.
Information from The Associated Press contributed to this report.