Liverpool boss Jurgen Klopp will be taking a major gamble if he decides to start Alisson against Manchester United so soon after his injury, according to Rivaldo. The Brazilian shot-stopper suffered a calf injury on the opening day of the Premier League season against Norwich in August and has since been replaced by summer signing Adrian between the sticks. However, the Brazil international has made tremendous progress as he completed a full training session at Melwood on Tuesday and is now in contention for the derby against United this Sunday at Old Trafford (4.30pm). But Rivaldo is worried that a return to the starting line-up could backfire so soon after Alisson’s injury and Klopp should probably pick Adrian in goal instead. The Barcelona legend, though, admits that the 27-year-old has amassed a lot of experience in the top level and understands how important it is for players like him to play in that kind of derby. The ex-AC Milan ace believes he should have probably played a few games before United but has full confidence that he will be solid in Liverpool’s goal. Rivaldo told Betfair: “This is his first match in a few months and perhaps it could be…