The Swiss Ace speedster failed to make any impression in four appearances in Melbourne during the late winter and spring.
His run of outs continued on his return when he beat only one runner home in the Counties Bowl in November at his last appearance.
"He seems pretty close to the mark again, but he does have to apply himself on raceday," McKee said.
"He usually goes well at Trentham and for Opie as well."
Bosson has ridden Passing Shot eight times for five wins and two placings, while the horse has been successful three times on the capital city course. He was also runner-up in the Wellington Guineas.
McKee will also be represented at Trentham by O'Rachael (3YO Premier), Poetic Affair (Kitchen Creators Premier) and Novelty (20th Anniversary Aurora Australis Premier).
- NZ Racing Desk