Up to eleven players are leaving Pittodrie this summer and the club will not be featuring in Europe after they were knocked out of the Scottish Cup by Queen of the South.
The Aberdeen manager failed in a bid for Gow in January 2007 and is expected to renew his interest over the coming weeks.
Another target Stephen Postma has rejected an initial offer from Aberdeen. The former Aston Villa defender's contract expires at the end of the season and Calderwood confirmed he is in the hunt for new players.
"I won't be saying anything until the players have been signed.
"I was hoping to get everything done by the end of May, but that might be difficult because there will be so many changes and a lot of negotiations to be done.
"I'm building a totally new team, so the job is a lot harder than when I came to Pittodrie four years ago.
"Back then it was just a matter of adding a few players to the squad and building it back up gradually.
"The changes are going to be massive this time and I won't have any problems getting a choice of players."