"I felt a knock and it's a bit swollen, but I don't think it's too serious. By Friday I'll be ready," he told reporters after a lengthy training session at Mogwase, near the team's Sun City base.
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Ghana play Uruguay on Friday at the Soccer City Stadium in Johannesburg.
Gyan sat with ice wrapped around his ankle and hobbled away after the practice but was adamant he would be in the starting line-up against Uruguay.
Missing from the session were captain John Mensah, midfielder Kevin-Prince Boateng and winger Dede Ayew, who all picked up knocks in the weekend's second round win over the United States.
Boateng has a hamstring injury, and is doubtful for Friday, and Mensah suffers from persistent back problems. Ayew is resting an ankle knock plus is suspended for the upcoming clash.
But central defender Isaac Vorsah, who has missed the last two matches for the Black Stars at the tournament in South Africa, participated throughout the training in the crisp night air at the small rural stadium.
Gyan, who has scored three of Ghana's four goals at the finals, said reaching the last eight was a massive achievement for the Black Stars.
"We are so happy to have qualified, it was so important for Ghana and the whole of Africa. We qualified for second round four years ago and this time we've made it to the quarters."
It was Gyan's spectacular extra-time volley that proved the winner in the 2-1 victory over the Americans at Rustenburg on Saturday.
"The goal was one of the best of my career. I was pushed from behind and I should have fallen down (to claim a penalty) but I resisted and I made it happen."
Thoughts of targeting the tournament's top scorer award, however, were not on his mind, he told Reuters.
"I'm only thinking about helping my team to win. The prize is not important, remember football is a collective game."
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