Per The Athletic's Andrew Baggarly, the Giants placed McCutchen on revocable trade waivers. He added there is a "very good chance" the 2013 National League MVP is playing for a new team by the end of this week.
The move comes after the Giants were swept by the Cincinnati Reds over the weekend and have lost eight of their past 12 games to fall 7.5 games out of the second wild-card spot in the NL entering Monday.
McCutchen is in the final season of his contract and will be eligible for free agency this offseason. If the Giants don't trade him, they can make him a qualifying offer to receive draft-pick compensation in 2019 if he signs elsewhere.
Under MLB's waiver rules, teams have the option to put in a claim on a player. Priority is determined based on the claiming team's record, but if no one puts in a claim and the player clears waivers, his team can negotiate a deal with any club.
In the event McCutchen is claimed, the Giants will have the option to simply pull him back to keep him, negotiate a trade with the claiming team within 48 hours or just give him to the other team for nothing.
McCutchen, 31, is having a solid season in San Francisco. He's hitting .257/.354/.417 with 42 extra-base hits and 10 stolen bases in 121 games.