With two key players suspended for the semifinals, Uruguay needs captain Diego Lugano to be healthy.
Lugano injured a right knee ligament in the quarter-final win against Ghana, but was able to jog during training Sunday, raising hopes he could be fit for Tuesday's match against the Netherlands in Cape Town.
"It's complicated because the time between matches is so short now," the central defender said. "But I was lucky enough to be able to train and run in straight lines, which is very favourable."
Uruguay, the 1930 and '50 World Cup winner, is through to the semifinals for the first time in 40 years.
The defence has been a major factor in the team's progress, allowing just two goals in five games. But injuries and suspensions will mean changes for the semifinal.
Fullback Jorge Fucile will miss the match after receiving a second yellow card against Ghana. Central defender Diego Godin missed Friday's quarter-final with a left thigh problem and is doubtful
Striker Luis Suarez is suspended for the last-minute red card he was shown for his handball on the goal line against Ghana.
Those absences make Lugano's recovery all the more important.
"The risk of pain is the last thing on my mind," Lugano said. "Everybody wants to play in these games, but the question is whether I'm physically 100 per cent to be able to play a game at this level."
The defender, who plays with Turkish club Fenerbahce, said a balance had to be struck between his desire to play and his conditioning.
"I have to be honest with the team and if I'm not able to play there are other players who can come in and do a good job," he said. "I'm doing everything I can to be fit and then the coaching staff and doctor will make a decision about whether I play."