Bristol Rovers defender Danny Coles is set for a summer spell of rehabilitation in the United States to aid his recovery from a knee injury.The 27-year-old has been out since October with cartilage damage. [LNB]He will spend up to a fortnight with specialist Bill Knowles to aid his recovery in time for the new season. [LNB]"Whatever happens we would like Danny back fully fit for the start of pre-season," Rovers first-team coach Paul Trollope told BBC Radio Bristol. [LNB]"If we can get that, it will be like signing another player. [LNB]"We're pleased with the latest round of rehab and hopefully that will continue through the summer." [LNB]Knowles, who is based in Vermont, has helped footballer Michael Owen and rugby World Cup winners Jonny Wilkinson and Richard Hill return to fitness after knee injuries. [LNB]Pirates physio Phil Kite told BBC Radio Bristol: "He's a rehab specialist and he's one of the top in the world, so he takes it to another level in terms of rehab training. [LNB]"Danny's had a lot of injuries in the past. He's had an anterior cruciate ligament reconstruction on the other knee and quite often you do get complications. [LNB]"Unfortunately he did, but he's through the worst of it now and hopefully with this intensive rehab programme and giving him time throughout the summer to get right, he'll be fit and raring to go for pre-season. [LNB]"If we were in the play-off positions we would have pushed to get him fit. [LNB]"But the fact that we're not means we can give him that extra two months to get fit in the summer and be absolutely spot on."