Maddocks departed the Rebels earlier this month to join the Waratahs, citing a personal desire to shift home.
Kellaway was disappointed to lose his former schoolmate without playing a game together, even if it could work in his favour.
“Jack’s a huge loss, he’s a very talented player,” Kellaway said on Tuesday.
“There’s lots of depth in the outside backs but it does make life a little easier for people like me trying to break in there.”