James McDonald has been forced to give up almost half of his Rosehill rides because of weight issues.

Firmly in the box seat to claim the 2013-2014 Sydney jockeys' premiership, McDonald can't make the weight on three horses who have been handicapped on 54kg on Saturday.

McDonald returned to riding this week after a month off and booted home a double at Canterbury on Wednesday to close the gap between himself and Nash Rawiller to two wins in the race for the jockeys' title.

With Rawiller enjoying a 10-week riding stint in Japan, McDonald is a clear-cut premiership favourite.

"I'd say we will probably speak to him (at the races) but as to what the circumstances are I'm not too sure," Racing NSW steward Ray Livingstone said.

"Obviously not riding makes it hard to keep your weight down all the time because he was riding 54kg relatively consistently before."

McDonald's weight dramas have contributed to an eventful comeback week for the New Zealand jockey who has made Sydney his home after being enticed across the Tasman by trainer John O'Shea.

He will start a six-meeting suspension next week for careless riding out of Canterbury while he called in sick for Thursday's provincial fixture at Wyong.

McDonald will miss out on the ride on Gai Waterhouse's Winter Cup runner Sir Bigglesworth at Rosehill.

And will also give up the mounts on two Hawkes Racing runners, Animoso and Cleansing Ale.

Bookmakers rate Truly Ready, a last-start winner on the Kensington track at Randwick, the pick of McDonald's five remaining Rosehill rides.