Free-agent third baseman Mike Moustakas is headed back to the Milwaukee Brewers on a one-year, $10 million deal, a league source confirmed to ESPN's Jeff Passan on Sunday. There is a mutual option on a second year.

The Athletic was first to report the agreement.

The left-handed-hitting Moustakas batted .251 with 28 homers and 95 RBIs in 152 games in 2018 with the Kansas City Royals and Brewers. He hit .256 with eight homers and 33 RBIs with the Brewers after being acquired from the last-place Royals on July 27 and helped bolster Milwaukee for its NL Central-winning stretch run.

Moustakas became a big hit with both fans and teammates on the Brewers in their drive to come within one game of reaching the World Series. They appreciated his solid third base defense, and his left-handed power stroke was key in getting Milwaukee through the NL Division Series. In the clubhouse, his focused demeanor and extensive postseason experience made him a source of steadiness for a club playing in the postseason for the first time since 2011.

Reigning NL MVP Christian Yelich expressed his excitement over Moustakas returning to the Brew Crew.

Moustakas was instrumental in helping Kansas City reach the World Series twice, including its championship run in 2015, and brought that pivotal playoff experience to bear as another key, power-hitting presence in the Milwaukee lineup.

Moustakas hit .364 in a three-game sweep of the Colorado Rockies in the NLDS with two RBIs. He had a game-ending, two-out RBI single in the 10th inning in Game 1 and an RBI single in the eighth inning of Game 2 to help break open what had been a 1-0 game.

Overall, the 30-year-old Moustakas has hit .217 with six homers and 18 RBIs in 41 games over nine postseason series.

The playoff run in Milwaukee wound down an eventful year for Moustakas that started with a disappointing offseason.

After setting the Royals' single-season home run record with 38 in 2017 and being named AL Comeback Player of the Year, Moustakas filed for free agency. He rejected a $17.4 million qualifying offer in November 2017.

Moustakas never received the multiyear mega-contract he and his agent, Scott Boras, had anticipated. The Royals signed Moustakas to a one-year, $6.5 million contract in March with a mutual option for 2019.

"It's definitely been an interesting year, but I'm very happy with the way everything turned out," Moustakas said in October. "I was able to sign back with Kansas City. I got traded here and now I'm in the postseason again. Everything happens for a reason."

Information from The Associated Press was used in this report.