Sunderland midfielder Jack Rodwell has suffered with a series of injury problems in recent seasons.
Rodwell has suffered with a series of injuries in recent times, and he visited a specialist in Germany during the week to try and find a solution to his fitness issues.
Allardyce is hoping that Rodwell can overcome his injury problems, as he feels that the central midfielder can play a big part for his side if he can get back to his best.
“Everybody is saying ‘what’s happened to Jack Rodwell,” Allardyce said.
“It’s clear that the amount of niggling injuries he has suffered over the last two years, at Manchester City and here, has caused him to lose his focus and confidence.
“We have to rebuild that and the only way we can do that is if we keep him fit.”
Rodwell showed great promise as a youngster at Everton, but a move to Manchester City has halted his career.
Rodwell barely played at the Etihad Stadium, and he has struggled to show his top form since moving to the Stadium of Light back in 2014.
Rodwell never showed his true qualities last season, and he has only played a peripheral role this time around.
The England international did put in an encouraging display after coming off the bench in a 3-1 defeat against Arsenal last weekend, though, and he will hope to build on that performance.
Sunderland’s next match comes against Watford this weekend, and they could move out the relegation zone with a win.