Unless he can successfully appeal a suspension, Glen Boss will miss two crucial autumn carnival meetings including the Golden Slipper.

Boss rode Cascadian in the Group Three Liverpool City Cup at Randwick on Saturday but his efforts to get clear running at the top of the straight resulted in a severe pounding to James McDonald's mount Imaging.

After being charged, Boss told stewards he wanted to "test the waters" by edging out around the home turn and trying for a run to the outside of eventual winner Quackerjack but he did not realise McDonald's mount was travelling so well.

As he attempted to shoulder out and McDonald tried to keep him in a pocket, the two horses made severe contact.

"I test the waters but I never went on with it," Boss said.

Chief steward Marc Van Gestel asked whether Boss should have returned to his original spot behind Quackerjack after the initial contact.

"I can't go back behind him because I'm close to Quackerjack's heels. I would be in danger," Boss said.

Stewards disagreed, saying the interference was in the high range and outed Boss from March 10 to 22.

The All-Star Mile is at Caulfield on March 14 and the Golden Slipper is at Rosehill a week later.