Jeff Monson-Jim York, Soa Palelei-Bob Sapp Co-Headline CFC 21 in Sydney

Promotion officials Sunday announced that the co-main events for CFC 21 will see Jeff Monson against “Big” Jim York (Pictured) and Soa Palelei versus Bob Sapp. Undercard bouts have yet to be announced for the show, which takes place May 18 at Homebush State Sports Centre at Sydney Olympic Park.

Monson, 41, is one of the sport’s most active and far-traveled heavyweights, having racked up nearly 60 bouts around the world in his 15-year career. The stocky grappler from American Top Team went 4-2 in 2011, but was soundly outpointed by Fedor Emelianenko and Daniel Cormier in his two high-profile appearances. Monson got back on track March 16 by grinding down Alexey Oleinik for a decision win in the main event of M-1 Challenge 31.

His opponent, 36-year-old New Zealander York, enters the bout on a four-fight win streak but has not recorded a bout since November 2010. Once expected to take part in the 10th season of “The Ultimate Fighter,” York reeled off his four in a row -- most notably choking out kickboxer Peter Graham in July 2010 -- in a five-month span after a disappointing run with Japan’s Sengoku promotion.

Best known for his one-and-done stint in the UFC, Palelei has torn through nearly all opposition in his home country since exiting the Octagon. The 34-year-old “Hulk” is 7-1 in his last eight starts, finishing all but one of his wins inside the first round. His only misstep in the past three years came in a November 2010 stoppage loss to Cormier.

Once a starring attraction in Japan’s Pride and K-1 Hero’s events, Sapp has won only one of his last nine outings; all eight losses have come via first-round stoppage or submission. “The Beast” is 0-2 so far in 2012, having tapped to strikes from Rolles Gracie in February before suffering a leg injury in his March 11 meeting with James Thompson in India.