Bolton have been dealt another injury blow with defender Sam Ricketts facing an indefinite spell on the sidelines.After losing Zat Knight for up to six weeks with an ankle ligament injury sustained in Sunday’s win over Everton in the Premier League, Bolton boss Owen Coyle can now add Ricketts to the casualty list.The 29-year-old damaged his Achilles during his side’s 1-0 win over Wigan in their FA Cup fourth-round replay at the DW Stadium and had to be carried off on a stretcher.”He has damaged his Achilles and it doesn’t look great at this time,” said Coyle.”The medical team think it could be quite severe and we hope that is not the scenario, but the way it is looking right now, I think it is going to be a lengthy period of time.”I think he just went to recover as Moses was raiding for Wigan, and it looked innocuous, but because of the speed the game is played at – he has certainly damaged his Achilles, that is for sure. I just need to find out the extent of it on Thursday when it is looked at properly.”