"Operations will commence as soon as sea states reach acceptable levels," BP said in a statement.
The oil giant had planned to start the procedure Monday.
Retired U.S. Coast Guard Adm. Thad Allen, the federal government's point man for the disaster, had said earlier BP crews were to begin work Monday to remove a "capping stack" that began trapping oil in the well last month, and that allows them to remove and replace the blowout preventer, CNN reported.
The blowout preventer is a safety valve at the top of the well.
Replacing the blowout preventer is a key step before engineers use a relief well to permanently kill the well 18,000 feet below the gulf's surface, Allen said.
"We will attempt to pull it free, and we are prepared to apply up to 80,000 (pounds) of force in addition to the weight of the blowout preventer to lift it," Allen said. "We call this the gentle tug."
After the relief well intercepts the crippled well, crews will use several days to permanently seal the well with mud and cement in a "bottom kill" procedure, CNN said.
The Deepwater Horizon drilling rig leased by BP exploded April 20, killing 11 workers, then sank two days later, dumping millions of barrels of oil into the gulf until a temporary cap contained the spill July 15.
Members of a Justice Department evidence recovery team will be at the site during the blowout preventer's removal, Allen said.