The duo are in the running for the prize after helping maintain Liverpool's title charge with three victories during the period.
Mane continued his rich vein of goalscoring form in March, finding the back of the net three times in four top-flight appearances.
Robertson, meanwhile, was ever-present in Liverpool's four league fixtures and delivered his ninth assist of the league season for the opening goal in the victory over Tottenham Hotspur.
Joining the pair on the shortlist are Seamus Coleman, Bernado Silva, Jamie Vardy and James Ward-Prowse.
Click here to cast a vote for Mane and Robertson.