Undisputed light heavyweight
champion Roy Jones Jr will concede a massive 33lb to WBA heavyweight champion John Ruiz in their title showdown on Saturday.
Stone (bottom left) and Merkerson (right) had to be restrained
Puerto Rican Ruiz weighed in at 226lb while the 34-year-old Jones tipped the scales at 193lb.
But the weigh-in in Las Vegas was marred by a brawl between Ruiz's manager Norman Stone and Jones' trainer Alton Merkerson.
The incident was sparked by an argument over fight gloves just before the weigh-in took place.
Stone was cut on the lip as punches were thrown and both men fell off the temporary stage.
Stone was stretchered off to hospital complaining of a pain in his side after the weigh-in.
Jones is attempting to become only the second ex-middleweight champion - and the first for over a century - to win a heavyweight title.
The only other man to achieve that feat was Bob Fitzsimmons in 1897.
Jones, whose record is 47-1 with 38 knockouts, last fought in September when he beat British boxer Clinton Woods in a sixth-round
He has won 13 fights in a row since his only defeat, a
disqualification against Montell Griffin in March, 1997.
Ruiz's record is 38-4 with one drawn.
The 31-year-old won the WBA title from Evander Holyfield in March 2001.
In his last fight back in July, Ruiz was a narrow winner over Kirk Johnson, who was disqualified in the 10th round for
repeated low blows.