Peterson has enjoyed a long and successful association with the stable, his highlight being as a part-owner of the Moroney-trained Brew, winner of the Melbourne Cup in 2000.
Meanwhile, Lock's focus will turn to Tavistock gelding Hiflyer who holds a nomination for this Saturday's Manco Easter Stakes at Ellerslie.
"The horse is well and Johnathan Parkes will come up to ride him again," he said.
Parkes rode Hiflyer for the first time earlier this month at Wellington where they comfortably accounted for the two-time group one winner Nashville on a heavy track.
"He wasn't 100 per cent happy in the ground and Johnathan said it was just his class," Lock said.
- NZ Racing Desk