Portugal striker Cristiano Ronaldo had his training session cut short Wednesday and was seen watching the remainder of his team's practice with an ice pack on his injured left knee.
According to ESPN, Ronaldo began practice without a bandage, but was forced to stop and treat his knee before leaving the field with the rest of the team.
Ronaldo's health was an issue entering the World Cup -- he was diagnosed with tendonitis before Brazil -- but he claimed he was 100 percent healthy before Portugal's first match.
And while that may be true, there are also reports Wednesday saying that Ronaldo's doctor has said that playing through this current injury could threaten the star's career. That's an awfully harsh conclusion to draw, but it's safe to assume Ronaldo isn't 100 percent.
Portugal will face the United States Sunday evening.