Rene Binder and Meindert van Buuren will become the fifth and sixth different driver to race for MP in GP2's 2015 season, making up its Monza lineup.
MP has picked up one podium courtesy of Sergio Canamasas this year and currently sits ninth in the teams' standings.
The team parted ways with Canamasas after three rounds and has now had to hire two new drivers, with other team regular Daniel de Jong getting injured last time out at Spa.
23-year-old Binder is in his third year of GP2, having started 2015 with Trident.
The Austrian had sat out Spa with an infection and has now split with the Italian team, instead linking up with MP.
Meanwhile, Dutch racer van Buuren will be making his GP2 debut as he switches over from Formula Renault 3.5.
The 20-year-old raced in FR3.5 with both Lotus and Pons this season, but both partnerships have allegedly ended in contractual difficulties, leading van Buuren back to MP - his former team in Formula Renault 2.0 and Auto GP.