Millwall striker Andy Keogh has given boss Kenny Jackett an injury worry ahead of his side's trip to Crystal Palace on Saturday.
Keogh suffered mild concussion in training over the weekend, which has ruled him out the Republic of Ireland's World Cup qualifier against the Farore Islands on Tuesday.
The 26-year-old has scored twice for the Lions so far this term and also netted the Republic's consolation goal in their 6-1 thrashing at the hands of Germany on Friday.
An FAI spokesman said: "Andy Keogh suffered a knock to the head in training on Saturday.
"He was observed overnight by the FAI medical team and has been ruled unfit to travel to the Faroe Islands due to mild concussion."