The Mets had received a 24-hour window to negotiate with the All-Star outfielder about waiving his no-trade clause. Shortly before an 8-2 win over the Reds on Wednesday night, Beltran arrived in the clubhouse and told his teammates he was on his way to join the Giants in Philadelphia.
"He came over and shook everybody's hands and said thank you," Mets outfielder Angel Pagan said. "We were very happy for him. He's going to be with a team that's a contender."
The Giants will finish a series in Philadelphia on Thursday night, then fly to Cincinnati for a three-game series this weekend, leaving Beltran with a back-and-forth trip.
His new team was eager to greet him.
"Having a guy like Beltran obviously adds a lot of positive energy," Giants closer Brian Wilson said. "With that kind of hitter, you're going to start seeing guys in front of him, guys hitting behind him, getting more pitches."
The All-Star slugger had the option to block any deal because he is a 14-year veteran who has spent the past seven seasons in New York, giving him 10-and-5 rights. Sources had told ESPN The Magazine's Buster Olney that Beltran would waive his no-trade clause after the Mets and Giants reached agreement on the deal.
A Mets source told ESPNNewYork.com's Adam Rubin the deal would be made official Thursday.
Earlier Wednesday, two sources with knowledge of the trade talks told ESPN The Magazine's Tim Kurkjian the Giants were closing in on a deal for Beltran.
As part of a package for Beltran, the Giants would include pitcher Zack Wheeler, sources told Olney. He is 7-5 with a 3.99 ERA in 16 starts for San Francisco's high Class-A affiliate in San Jose. The Giants selected Wheeler with the No. 6 pick in the 2009 draft.
To complete the deal, the Mets will pick up $4 million of the $6.5 million that Beltran has left on his contract.
"While we have been engaged in discussions, we're not in position to comment at this time," the Mets said in a statement.
Manager Terry Collins was told to hold Beltran, who was not at batting practice Wednesday, out of the lineup. It is the second major trade for the Mets, who dealt closer Francisco Rodriguez to Milwaukee after the All-Star Game.
"Everyone here has anticipated it, whether we like it or not," Collins said. "We knew it was going to happen. We've talked about it for the last 10 days. So we'll find out tomorrow."
Giants general manager Brian Sabean recently talked about upgrading the Giants' roster, and it appears he's added a talented slugger in the middle of a comeback year.
"He's a complete player," San Francisco manager Bruce Bochy said, declining to talk about the trade specifically. "Carlos has all the tools that you look for in a player. He has great instincts for the game. Plays the game hard, plays the game right. I still remember when Houston got him and the job he did there.
"He's a tremendous all-around player. He's one of the elite players of the game."
Bochy acknowledged that the San Francisco offense needs a lift. The Giants rank 15th in the National League with 371 runs scored.
When Beltran signed his seven-year, $119 million contract with the Mets in January 2005, it included a complete no-trade clause that required him to give permission before the Mets deal him.
Sources told Olney on Wednesday that the Cleveland Indians offered to take on Beltran's entire salary for the rest of the year, but were told that the outfielder would not consider going to Cleveland. The Indians walked away from the talks convinced that Beltran's agent, Scott Boras, is in control of the process.
"While I won't comment on specific players, we are continuing to work to try to improve the team and haven't limited ourselves in the alternatives we've considered," Indians general manager Chris Antonetti told The Associated Press in an email.
Amid speculation that Beltran might be hesitant to leave the National League for an American League team, Boras told ESPN.com's Jerry Crasnick on Tuesday that one factor trumps all.
"This decision for Carlos is about the select group of teams where he feels he has a great chance to win," Boras said. "That's what this thing is about."
Beltran also has said he is not interested in serving as a designated hitter.
Shortstop Jose Reyes said Beltran took teammates to a local steakhouse owned by one of his friends following an 8-6 win over the Reds on Tuesday night.
"We were joking with him: 'You're doing this because you're going to get traded,' " Reyes said. "He said, 'No, no.' "
Reyes said losing Beltran will be a huge blow to the Mets.
"You lose a guy like that in July, it's big, it's huge," Reyes said. "We've got to continue to play with what we've got. It's not easy to replace that kind of player. It's going to be tough."
Collins said Lucas Duda would play in right field a lot after Beltran is gone.
"I'm probably more comfortable at first base and left field because I haven't played a lot out there," Duda said. "I'll try my best out there and see what happens."
"He'd better get comfortable real fast," Collins said.
Pitcher R.A. Dickey has known Beltran since 2000 and will miss having him in the clubhouse.
"He's a very complete individual, not only on the field but off," Dickey said. "He's a valuable piece that's leaving. It's kind of sad."
Information from ESPN The Magazine's Tim Kurkjian, ESPN The Magazine's Buster Olney, ESPN.com's Jerry Crasnick, ESPNNewYork.com's Adam Rubin and The Associated Press was used in this report.