Dusty Baker was a big dipper. He's cut back on his chewing over the years, but still might pop in a pinch when games get tight.

The Washington Nationals manager won't get that choice at some ballparks this season.

Big leaguers are now getting a reminder that smokeless tobacco is banned at stadiums in San Francisco, Los Angeles and Boston.

One-page letters are being put in clubhouse lockers throughout spring training. The notices come jointly from Major League Baseball and the players' union.

"It's a bad influence for the kids. Big time. I'll say that. But also they're adults, too, at the same time," Baker said.

Local laws will prohibit the use of all tobacco products at Fenway Park, Dodger Stadium and AT&T Park this year, meaning players, team personnel, umpires and fans. The letter advises the same ban will take effect at every California ballpark in December.

"I support it," new Dodgers manager Dave Roberts said. "I think that the intentions are there, and there's obviously going to be some resistance with players."

"Like it or not, players are role models, and we have a platform as coaches and players. So if that's the law, then we definitely support it," he said.

MLB to offer therapy

The letter being distributed to players on 40-man rosters and teams this spring says: "Please note that these are city ordinances and not rules established by Major League Baseball. However, the commissioner's office will be monitoring players and club personnel for compliance with the regulations."

Smokeless tobacco isn't permitted throughout the minor leagues. There is no ban on dipping in the majors, and the issue is certain to be discussed in upcoming labour talks between MLB and the union on the contract that expires Dec. 1.

Players, managers and coaches now can't stick tobacco tins, cans or pouches in their pockets when they're on the field or in plain sight of fans. No wads stuck in the mouth during TV interviews, either.

In their letter, MLB and the union said it would provide "nicotine replacement therapy products to those players who wish to use them as substitutes. A shipment of various products including lozenges, gum, and patches will be sent to each club free of charge in spring training, and throughout the 2016 season."

Toronto Blue Jays manager John Gibbons applauded the effort to cut down on chewing tobacco. He quit a couple years ago after Hall of Famer Tony Gwynn — a career-long dipper — died at 54 of salivary gland cancer.

"I wouldn't want my kids doing it. You hope in some way, they can eliminate it and wipe it out. I'm sure there will be some fights over that, especially in this election year. I'm sure that'll be brought up. But, hey, if you can get rid of it, I'm all for that," he said.