Teddy and Bill get out in front of George during the Presidents Race on opening day at Nationals Park. Bill picked a fight with Teddy and allowed George an easy victory. (Jonathan Newton/The Washington Post)

If you go to a Washington Nationals game this season, you might notice some new faces at Nationals Park.

Denard Span is now the Nats’ super-fast center fielder and leadoff hitter. Dan Haren is a new starting pitcher. Rafael Soriano is a hard-throwing reliever.

And there’s one more new face: William Howard Taft, or, as the Nationals call him, Bill. Just who is Bill? He’s the Nats’ new Racing President.

The popular race of big-headed mascots that happens at every Nats home game now has a fifth competitor.

Taft is not as well known as the other presidents with mascots who race around the outfield: George Washington, Thomas Jefferson, Abraham Lincoln and Teddy Roosevelt. After all, the first three in that powerful lineup have monuments around Washington. Roosevelt has an island named after him in the Potomac River.

President William Howard Taft was a baseball fan. He was the first president to throw out a first pitch on opening day. (Harris & Ewing Photographic News Service)

Most historians — those are people who study history — wouldn’t put Taft in the category of great presidents. He served from 1909 to 1913, right after Teddy Roosevelt. And not only did the voters not reelect Taft in 1912, he finished third, behind Woodrow Wilson and Roosevelt.

But Taft did not stop trying to help his country. In 1921, President Warren Harding appointed Taft to the Supreme Court as its chief justice. That court has nine judges (they’re called justices) who decide the most important legal cases in the country. Taft is the only person to have been president and a Supreme Court justice.

Historians generally agree that Taft was a better justice than he was a president. That’s a good lesson for kids. Even very famous and smart people are often better at one job than another.

But the real question now is: How good a Racing President will Bill be? Taft was a baseball fan. He was the first president to throw out a first pitch on opening day. He did that at a Washington Senators game in 1910.

My guess, however, is that Bill won’t be very fast.

According to historians, Taft was the heaviest president ever, weighing more than 300 pounds. President Taft had a special bathtub made for him in the White House. It was so big that four regular-size men would fit in it. In Monday’s home opener, Bill threw his weight around by pushing Abe to the ground and picking a fight with Teddy. (George easily won the race.)

So, root for Bill. He might need all the fans he can get.

Fred Bowen writes the sports opinion column for KidsPost. He is the author of 19 sports books for kids. His latest baseball book, “Perfect Game,” has just been published.