Maiga joined Metz last season on a one-year loan deal with an option to buy. But that deal failed to materialise after Metz were relegated.
The player signed for West Ham for a reported £4.7m from Sochaux, scoring seven goals for the Hammers in 40 appearances.
Metz were thought to paying just 20 per cent of Maiga’s £30,000-per-week salary last season, and the Hammers are said to be keen to get him off the wage bill.
He has just under one year remaining on his West Ham contract, which means he pockets around £1.5m.