ST. LOUIS — The trip was optional for Christian Yelich; the change in teams was not. This was late January, and Yelich had just been traded to the Milwaukee Brewers, who suddenly controlled his rights for the next five seasons. Yelich lives in Southern California and had pledged his prime to the Miami Marlins. Now, just a few weeks from spring training, he was asked if he wanted to visit his new summer home — in the winter.

Yelich was eager to go. He had no close friends on the Brewers, and with the team hosting its annual off-season fan event, he would have a chance to meet new teammates. First, though, he would meet the dignitaries of the franchise — and he found that he fit right in.

Mark Attanasio, the team owner who runs an asset-management firm in Los Angeles, offered to fly Yelich to Milwaukee on his private plane, a Challenger with facing club chairs in the front and a table and a couch in the back. Yelich had never met Attanasio but knew his son, Michael, through mutual friends. Michael would be on the flight from the Van Nuys airport, too, along with another Southern California resident: Ryan Braun, the veteran outfielder and the last Brewer to win the Most Valuable Player Award, in 2011.

This was not a direct flight, but nobody minded. On the way to Milwaukee, the group stopped in Scottsdale, Ariz., to pick up another former Brewers M.V.P. — the Hall of Famer Robin Yount, a two-time winner who lives nearby. Yount boarded the flight with Bob Uecker, the famed team broadcaster and funnyman.