The 29-year-old defender has penned a four-year contract with the Whites after being told he was not guaranteed a first-team spot at Sheffield United despite only joining the club in the summer.
Whites boss Grayson is still looking at strengthening further but admits he is not desperate to add to his squad before Tuesday's 5pm deadline.
He told the club's official website: "It may be that there is a bit more movement.
"There's a couple of things we're looking at, but in terms of incomings I'm fairly comfortable about what we have so we'll just have to see.
"More likely is that one or two players might head out, either on Tuesday or when the loan window opens next week."