Youngsters Carlos Roca and Craig Fleming have also been told that they won't be offered new contracts and can look for new clubs. They both failed to make a good enough impression on new manager Brian Talbot.
Calvin had a terrific start to his Latics career scoring six goals before having a lengthy layout with back problems and he has never been the same since. Talbot quickly saw that Calvin wasn't producing the goods in the first team and dropped him to the reserves where he hasn't pushed his way back into the starting lineup.
Carlos made his debut from the bench on the opening day of the season against Brighton & Hove Albion and made an instant impression on the Oldham fans with his skill and trickery. He made his full debut in the following game against Scunthorpe United in the Carling Cup. He went on to start two games this season and nine from the bench.
Craig has had very limited first team action, coming on for the last few minutes at Blackpool in January.
Danny Forde the current captain of the youth team has been offered a one year extention to his contract. Danny hasn't made a first team appearance so far but he captained the youths to league and cup silverware.