Cain has passed his physical, the source said, and the Brewers likely will formally introduce him on Friday.
“We’ve got a chance to be pretty good,” Cain told MLB.com on Thursday night. “I’m looking forward to doing whatever I can to help. It would seem we’re a playoff contender.
“… The chance to come home like that, so to speak, meant a lot. That’s the team that drafted me, developed me. I got my first hit with them, my first home run. It means a lot to go back there. I want to win.”
Cain’s new contract is for the longest term and biggest payout of any MLB free-agent deal this offseason. It surpasses Carlos Santana‘s three-year, guaranteed $60 million contract with the Philadelphia Phillies in December.
The deal includes no-trade protection and award bonuses of $300,000 for each All-Star team Cain makes and $500,000 for an MVP Award, the source said.
Cain, 31, returns to the organization where he began his professional career. He was a 17th-round pick by the Brewers out of Madison County High School in Florida in 2004 and broke into the majors with Milwaukee in 2010.
The following year, the Brewers sent Cain, Alcides Escobar, Jake Odorizzi and Jeremy Jeffress to Kansas City in a trade for pitcher Zack Greinke. Cain made the 2015 All-Star team, finished third in American League MVP balloting and was a pivotal member of Kansas City’s ’15 World Championship team.
Cain, who hit .289 with 56 home runs and 308 RBIs in 713 games with Kansas City, thanked Royals fans for their support over the years.
“I absolutely love Royals fans,” Cain said. “They loved on me for so many years. Just thinking of them brings a smile to my face. Man, I’m really going to miss them. Just all the support they gave me. It was incredible. We all went through so much together.”
Cain is a career .290 hitter who is known as an exceptional defender. He was an AL Gold Glove finalist in center field last season along with Toronto’s Kevin Pillar and Minnesota’s Byron Buxton, who won the award.
The Chicago Cubs, Los Angeles Dodgers, San Francisco Giants, Cleveland Indians and Toronto Blue Jays were among the other clubs that had expressed interest in Cain before he reached agreement with Milwaukee.