Ricketts damaged his Achilles in Wednesday evening's fourth-round replay at Wigan, which the Trotters won 1-0. He went to ground in the second half at the DW Stadium while tracking Latics substitute Victor Moses and had to be carried off on a stretcher. Coyle, who expects Zat Knight to be out for four to six weeks after the centre-back sustained an ankle ligament injury in Sunday's win over Everton in the Premier League, confirmed Ricketts had an Achilles problem and is likely to be sidelined for some considerable time. "He has damaged his Achilles and it doesn't look great at this time," said Coyle, whose team ran out winners thanks to Ivan Klasnic's 66th-minute goal. "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 when it is looked at properly." Coyle was delighted with the manner of the victory, which has set up a fifth-round tie at Fulham to be played on Sunday afternoon. Klasnic's winner, converted on the turn after he had collected Mark Davies' pass, made amends for the Croatian's failure to finish a one-on-one opportunity in the first half, and Coyle admitted his side should have beaten Wigan by a greater margin. "I though from start to finish, we were terrific," Coyle said. "We have won the game 1-0 and if the truth be told, there certainly should have been a few more goals. "We had six changes from the team that beat Everton and the ones that came in showed a real freshness and energy. "Obviously we are disappointed about Sam Ricketts' injury, but the positives to take from the game were there for everyone to see." Wigan boss Roberto Martinez, who went even further than Coyle in making nine changes to the Latics team, did his best to remain upbeat in defeat, focusing on the performances of three unnamed players he thinks can boost the club's battle for top-flight survival. He also claimed the "soft" pitch, which is being relaid on Thursday, worked against his team and insisted he was not disappointed that the match attendance had been just 7,515. "I felt some of the individual performances were very good and that is a positive," said Martinez, who confirmed young striker Callum McManaman had to have stitches to a head wound after a high challenge by Fabrice Muamba. "But as a team, we couldn't adapt to the pitch, which didn't help us to put three or four passes together. We found it quite difficult and Bolton adapted a lot better. "From our point of view, it (the performance) has given us three new players for the next 11 games of the season and quite clearly, we need to relay the pitch so we have a pitch where we can play our football." Coyle also felt the surface was sub-standard. The Scot said: "I felt the pitch does Roberto and Wigan a disservice, because they are a team who likes to pass and move the ball and I don't think the pitch helps them at all."
