But first, the Mets are counting on their big-name newcomer to hold down the fort at shortstop for a while.
Baez, a two-time All-Star and 2020 Gold Glove winner, gives New York an immediate fill-in for Lindor. The star shortstop, obtained from Cleveland in a blockbuster deal last winter, is sidelined with a strained oblique and not expected back until at least mid-to-late August.
"I'm super excited. I couldn't be happier," Lindor said. "I can't wait for him to come out here and put on a show for everybody."
Baez, who can become a free agent after the season, is batting .248 with 22 home runs and 65 RBIs. He has a .775 OPS and 13 stolen bases in 16 tries, but also leads the National League with 131 strikeouts. He has made 18 errors in 88 games.
"We think he adds a lot, brings a ton of energy to our team," Mets acting general manager Zack Scott said. "Knows how to win, knows how to do a lot of things to help us win. Plays elite defense, and baserunning and power."
Baez and Lindor both went to high school in Florida and played against each other in front of scores of scouts. They were drafted back-to-back in 2011, with Lindor going eighth overall to Cleveland and Baez ninth to the Cubs. They were teammates with Puerto Rico in the World Baseball Classic.
"I'm really excited to play next to him,'' said Baez, expected to join the Mets in time for Saturday night's home game against Cincinnati.
Both are energetic players with an entertaining flair. Baez's boisterous antics sometimes rankle opponents.
"He knows some people on our team, obviously," Scott said. "He's been very vocal about wanting to play with Francisco, which he'll get an opportunity to do at some point when Francisco's back playing for us. But we just think this really makes our team pretty deep and versatile. So we're excited to have him."
When Lindor returns, Baez could move to second base or even third if needed. At second, he and Lindor would make for a slick double-play combination.
"He fits a direct positional need right now with Francisco being out for a little while. But he is also excited to move around and, as he's said publicly even before coming here, that he'd be willing to move around the diamond," Scott said. "And so he provides that versatility that I've also talked about when Francisco does return and takes over at shortstop."
New York has Jeff McNeil at second base and J.D. Davis at third, with Jonathan Villar and Luis Guillorme also getting significant playing time in the infield this season due in large part to injuries and their own fine play. Villar and Guillorme have been filling in at shortstop for Lindor.
"There's plenty of time to have that dialogue and feel things out for what makes the most sense with the roster," Scott said. "Things change daily around here this year. For right now, though, we know where [Baez] is going to be."
Williams was optioned to Triple-A Syracuse, but also is a meaningful addition for a Mets team that was eager to reinforce a thin starting rotation depleted by injuries.
Williams is 4-2 with a 5.06 ERA in 13 games (12 starts) this season, his first with the Cubs after spending his first five years in Pittsburgh. The 29-year-old right-hander is eligible for arbitration after this season and can become a free agent following the 2022 season.
"I told him he's definitely going to be part of what we're trying to do here," Scott said.
The Mets also received cash as part of the deal.
New York began the day with a 3 1/2-game lead in the NL East over Philadelphia, and third-place Atlanta was four back. Both those teams also made moves before Friday's trade deadline in an effort to upgrade and chase down the Mets.
Before the deal for Baez and Williams, the Mets acquired veteran left-hander Rich Hill from Tampa Bay last week and plugged him into the rotation.
"We definitely tried and explored a lot of different things," Scott said. "We just didn't match up on everything. But we tried several things. We did bring in, like I said, depth pitching."
The 19-year-old Armstrong, a first-round draft pick out of high school last year, is sidelined with a right shoulder injury. A left-handed thrower, he is considered an elite defender in center field.
Crow-Armstrong played six games this season for Class A St. Lucie before getting hurt in May. He was 10 for 24 (.417) with two doubles, four RBI, two stolen bases, seven walks and six strikeouts.
The move was one of several by the disappointing Cubs in the days leading up to the deadline. Ready to rebuild, Chicago also traded away first baseman Anthony Rizzo, slugger Kris Bryant and closer Craig Kimbrel, plus other pieces.
The Associated Press contributed to this report.