Interstate gallopers are prominent in betting for the Group Three Summer Cup with Le Roi favourite to win in a third state this campaign.

But the absence of last-start Werribee Cup winner Unusual Suspect and Christmas Cup winner Cantonese from the field has resulted in weights for the 2400m Boxing Day feature at Rosehill raised 4kg.

A field of eight was declared on Friday with the South Australian-trained Le Roi installed favourite at $3.20.

Brisbane stayer Poste Restante is on the third line of TAB betting at $4.60.

Trainer Bjorn Baker is targeting the Perth Cup on January 1 instead of the Summer Cup and Cantonese arrived in Western Australia on Friday.

He had been nominated for the Rosehill race as a precaution in case he couldn't get a flight to Perth.

Unusual Suspect had been given 59kg when weights were declared.

All eight acceptances, which originally had the limit 54kg, will carry 58kg.

European import Le Roi has shown himself to be a stayer on the rise with three straight wins.

Two wins in Adelaide were followed by a 2-3/4-length victory over 2000m at Caulfield.

The field also includes Christmas Cup runner-up Iggi Pop.