Matt Williams, at left, is expected to become the Nationals’ next manager. Fans hope he will take the team back to the playoffs. (Dustin Bradford/Getty Images)

The Washington Nationals will name Matt Williams as their new manager after the World Series, according to several recent news reports.

Nats fans hope that Williams, who has never managed in the major leagues, will lead the team back to the playoffs and maybe even to the World Series.

Pro and college teams change their managers and head coaches all the time. For example, 13 of the 30 National Basketball Association teams have a new head coach this season.

All this hiring and firing makes me wonder: How much difference does the manager or head coach make?

It seems to me that Williams, like any manager or head coach, could make a big difference. After all, he will help select the players who will play for the team. As manager, Williams will place them at positions and in situations where, hopefully, they have a chance to succeed.

Williams will also try to get the players to play hard and work together when the going gets rough during the long 162-game season.

Finally, Williams will make key in-game decisions, such as when to change pitchers or pinch-hit for certain players.

So there’s a lot for a manager or head coach to do. But the players still have to play their best. If Ryan Zimmerman, Jayson Werth and Bryce Harper don’t hit and Stephen Strasburg, Jordan Zimmermann and Gio Gonzalez don’t pitch well, there isn’t much chance that Williams will be a winning manager.

A very famous baseball manager, Casey Stengel, said after his New York Yankees had won a seventh World Series under his leadership, “I couldn’t have done it without my players.”

One more thing: Pro coaches are judged on their wins and losses. If Williams doesn’t win, he won’t last long.

Kids, of course, have coaches, too. I have coached more than 30 kids teams over the years, and I know that a good coach can make a big difference.

Kids coaches organize the practices so the kids are playing and not just standing around. They also should encourage all of the players — not just the best players — to improve. Good coaches can teach kids the skills they will need in the games as well as how to be good sports.

But unlike pro coaches, a kids coach should not be judged on whether her team wins. After all, most kids will never become pros. It’s enough for kids to learn the fundamentals of the game and have fun.

A friend of mine who coached lots of kids teams put it best. “When you coach kids,” he said, “it isn’t how many you win or lose; it’s how many kids sign up for next season.”

Bowen writes the sports opinion column for KidsPost. He is the author of 18 sports books for kids that combine sports fiction and sports history. His latest book is “Perfect Game.”