Johnson, who had used his no-trade rights to block the deal earlier yesterday, changed his mind after getting an additional $1 million to make up for the fact that there is no state income tax in Florida.
"We got some tax elements taken care of in the transfer, so the monetary element would remain the same in Colorado," agent Scott Boras told the Associated Press. "My understanding is that this was the final step."
But Rockies spokesman Jay Alves said the deal had not quite been completed. "The trade has been reignited and we are talking again," he said. "We've got some things to work out yet."
A Marlins spokesman refused to comment.
When the trade is finalized, Johnson is to go to Colorado along with outfielder Preston Wilson, lefthanded reliever Vic Darensbourg and second-base prospect Pablo Ozuna.
Hampton and outfielder Juan Pierre would head for Florida.
Hampton, who also had a no-trade clause, agreed to the deal earlier yesterday. Both players maintain their no-trade rights with their new teams.
The transaction will raise the Rockies' payroll initially but provide long-term relief from Hampton's record-setting eight-year, $121 million contract with Colorado.
Hampton is guaranteed $84.5 million over the next six years, and has deferred $19 million of his signing bonus. The Rockies will pay $11 million of Hampton's remaining salary and the signing bonus.
Johnson has $25 million coming over the next three seasons, and Wilson is owed $27.5 million the next three years.
Hampton, 30, was 7-15 with a 6.15 ERA this year - the highest in the major leagues among pitchers who qualified for the ERA title.
He is 21-28 with a 5.75 ERA since leaving the New York Mets to sign the richest deal ever with the Rockies in December 2000. Following a 9-2 start in 2001, he is 12-26 with a 6.62 ERA.
