Thames, 30, has played 181 games in the majors, with a .250 average and 21 homers. He has just three major league stolen bases, but stole 40 for the Dinos in 2015. He has a .296 on-base percentage in the majors, but had a .450 mark in the K.B.O., where ballparks tend to be small and the talent level is considered to be below that of the Japanese league.

The Brewers did not scout Thames in person, but did study him extensively on video. Pitchers feared Thames and rarely challenged him with fastballs, but he displayed discipline at the plate, laying off junk and waiting for breaking balls he could mash. The pitch patterns will be different now, but the Brewers believe Thames can handle them.

“He’s going to see more consistent velocity than he’s seen the past couple of years, but I think he’s frankly looking forward to that,” Stearns said. “It’s a more normal style of hitting than constantly trying to guess which shade of breaking ball he’s going to see.”

Thames is eager for those fastballs, and everything else about the major league life. He made good money in South Korea — about $3.5 million, plus a Kia Sorento for winning the Most Valuable Player Award in 2015. But some of the game’s customs there grew tiresome, like the emphasis on bunting and the practice of dressing in full uniform at the hotel before road games. And while Thames had a few American teammates, communication with others was limited.

Thames was essentially his own hitting coach with the Dinos, and reinvented his approach. He watched interviews on technique with stars like the Detroit sluggers Miguel Cabrera and Victor Martinez, absorbing their lessons and teaching himself a new swing after finding his old one too inconsistent.

“I’d be very uphill, so a lot of balls I’d hit would have topspin,” Thames said. “If I got it perfect, it’d be a home run, but if I just missed it a little bit, topspin, so it would be off the wall or even knuckle and it wouldn’t travel as far. Now I work hard to stay short to the ball but have a flat path — finish flat, not just try to be up there hitting dingers all day.”

By not swinging for the fences, Thames began clearing them regularly. As a left-handed-hitting first baseman with power, a thick beard and a relatively short frame (6 feet), Thames recalls a former Brewer, Prince Fielder. His path to Milwaukee was just a lot less conventional.