McGregor says scans yesterday cleared Buderus of any new damage and the hooker will jog this morning and run again this afternoon as he attempts to shake the lower back problem that has disrupted his preparation.
Blues centre Timana Tahu also remains in doubt for the match and was reported to have a viral illness after missing training yesterday. McGregor says Tahu's complaint is "a little more serious" than flu but both he and Buderus will be in contention to play right up until tomorrow night.
In the Maroons camp, coach Mal Meninga says he's relaxed and very pleased with Queensland's preparation for tomorrow night's State of Origin rugby league series opener in Sydney. The Queenslanders, who've spent eight days in camp on the Sunshine Coast, head to Sydney today looking for their first victory in 11 visits to Telstra Stadium.
Meninga says his seven rookies have been schooled by former greats as to what Origin means and he's confident they will handle the intensity of tomorrow night's battle. He says he won't be seeking a meeting with referee Sean Hampstead before the game to clarify any points with him.
The Maroons will have a closed training run in Sydney's western suburbs late this afternoon but have no injury concerns on the eve of the game.