The pair had a bust-up during Thursday’s session, exchanging words before squaring up to each other, with Richards having to be restrained by team-mates.
However, the two are believed to have settled their differences after the session and shook hands in the dressing room, with Richards later revealing on his Twitter page that the incident had blown over.
He said: “Me & mario are all good! these things happen in training & we shook hands after. it shows passion!"
Balotelli has previously been involved in training ground bust-ups with Jerome Boateng and Vincent Kompany, whilst boss Roberto Mancini will not be impressed by this latest example of indiscipline, after the striker reportedly broke curfew just 48 hours before the 2-1 defeat to Manchester City on Monday.