Asamoah Gyan is a major concern for Ghana ahead of their Africa Cup of Nations Group D match against Mali after limping off training on Thursday.The 25-year-old felt pains in his right ankle, a problem he picked up during the opener against Botswana, and had to abandon the session midway.He however partook in the earlier jogging and stretches exercises but was unable to do the kick about.GHANAsoccernet.com sources reveal the decision to leave training was just a precautionary measure.Ghana will hold its final training sessions on Friday before facing off with Mali at the Stade de Franceville on Saturday.