Former West Ham and Fulham defender Paintsil, ex-QPR winger Cook and midfielder Croft, who left Oldham this summer, have featured for the Lions in their recent pre-season friendlies.
But boss Steve Lomas has decide to look elsewhere for new faces and all three have now moved on.
However, former Reading full-back Nicky Shorey has another chance to impress in Saturday's friendly against Gillingham.
Ex-West Ham forward Marlon Harewood is also training with the club but will not be involved against the Gills.
- Sports & Recreation
- Nicky Shorey
- Steve Lomas
- Marlon Harewood