The striker's manager at LA Galaxy says he missed their game with DC United with a knock but would not go into specifics about what the injury was.
Galaxy manager Bruce Arena says Keane will be monitored on a day to day basis.
Meanwhile West Ham United midfielder Mark Noble is set to make himself available to the Republic of Ireland, according to reports in the Daily Mail this morning.
The former England Under-21 international missed out on a call-up to an experiemental squad chosen by Roy Hodgson this week.
27 year old Noble is eligible to play for Ireland through his Cork-born grandparents – he could be available for the Euro qualifier against Germany on October 14th.