Grayson has already signed former Swindon striker Billy Paynter, 'keeper Kasper Schmeichel from Notts County and defenders Paul Connolly and Fede Bessone from Derby and Swansea respectively.
Grayson said: "We're still ongoing with a few things. We're speaking with players and agents. There's things going on all the time. I like to be quiet and spring a few surprises on people but whether that's this week, next week, or after, we'll do things in our own time."