Bosson hasn't ridden since he was stood down on Queensland Derby day with a viral infection and is booked to leave at the end of this month on a European holiday, as is Leith Innes, who copped a 12-day suspension for his ride on Counterattack in the Stradbroke Handicap, compounded by a four-day ban for careless riding at Ruakaka.
Grylls is on holiday in Tahiti and on his return will be taking up a three-month contract in Singapore.
Waddell's season was prematurely ended by a trackwork fall in April, after which he opted to bring forward surgery to remove a plate and screws in his leg from a soccer injury more than a year ago.
In other jockey news, Matt Cameron is on a three-week break and apprentice Rachael Goldsbury has a three-week stint in Queensland.
Other riders with overseas ventures are Danielle Johnson, who will participate in an international female jockeys' series in Sweden next month, and Cameron Lammas, who has accepted an invitation to ride at two meetings in Inner Mongolia.
- NZ Racing Desk