Saturday night’s UFC 240 is now down to 11 bouts after a positive drug test by Giacomo Lemos forced the cancellation of his heavyweight clash with Tanner Boser, sources confirmed to MMA Fighting. MMAjunkie first reported the news.

It’s still unclear which substance Lemos tested positive for, sources said.

Lemos signed with the UFC after going 6-0 around Brazil and South Korea over the past three years, winning all his fights by stoppage.

Boser (16-5-1), who was also scheduled to make his Octagon debut at Saturday’s event in Edmonton, Canada, joined the UFC after stopping Jared Kilkenny in the fourth round to win the Unified MMA heavyweight belt in May.

UFC 240 will take place at the Rogers Place in Edmonton and airs live on pay-per-view. Featherweight king Max Holloway defends his belt against Frankie Edgar in the main event, while former champion Cris Cyborg faces unbeaten Felicia Spencer in the co-main event.