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 counterattack 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 news 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 -- which 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.
Mexico scraped out a 1-0 victory over Jamaica in their Group B opener in the Copa América on Saturday, but their joy at making a winning start was tempered by what appeared to be a potentially tournament-ending injury to captain Edson Álvarez.
Álvarez collapsed clutching his hamstring in the 30th minute and limped off the pitch in tears.
Jamaica, who are ranked 38 places below Mexico, thought they had scored their first-ever Copa América goal when Michail Antonio headed into the net five minutes into the second half, but the goal was ruled out for offside by the video assistant.
Mexico stepped up a gear after that scare, with Luis Chávez, Santiago Giménez and Gerardo Arteaga all drawing fine saves from Jamaica keeper Jahmali Waite, before Arteaga finally broke the deadlock in the 69th minute with a thunderous strike.
Mexico, who are making their 11th appearance in the Copa América, reached the final in 1993 and 2001.
Both teams had relatively inexperienced goalkeepers. Julio González made his third start for Mexico after veteran Guillermo Ochoa was dropped from the squad and his predecessor Luis Malagón was injured recently.
Waite got the nod for Jamaica because Andre Blake, a two-time Major League Soccer Goalkeeper of the Year for the Philadelphia Union, was injured before the tournament. Waite made eight saves.
The result moved Mexico level on three points with Venezuela, who beat Ecuador 2-1 in the other Group B clash earlier in the day.
Jamaica play Ecuador in Las Vegas on Wednesday, while Mexico faces Venezuela in Inglewood, California.