General manager Mike Marshall says she fits in well, "you don't notice that she's five-foot-nothing, 120 pounds."
In the dugout she seems to be just one of the guys. But the 18-year-old who arrived from Japan just a few months ago is crossing barriers of culture, gender, tradition -- and language, still struggling to learn English. But baseball comes easy.
Though other players tower over her, on the mound the knuckleball is a big equalizer.
"I thought maybe this is the way that I can compete with men," Yoshida said. "If I can master it."
UC Berkeley's Bob Jacobsensays it's all a matter of physics. A well-pitched knuckleball doesn't spin. With no spin just air friction on the seams changes the ball's movement unpredictably.
"Half an inch is more than enough to ruin the batter's day," Jacobsen said.
So why doesn't everyone throw the knuckleball?
"It's not that easy," sayd Tim Wakefield, the knuckleball-throwing pitcher for the Boston Red Sox.
Yoshida said she was "mesmerized" by watching Wakefield's signature pitch. When the two met, Wakefield gave her some tips.
"To have her try to pick up and carry the torch for our little fraternity of knuckleballers," Wakefield said, "was pretty amazing."
Yoshida may not always get the batters out, but she's helping to fill the stands in Chico.
Even Baseball's Hall of Fame came to collect Yoshida's jersey from her first game - a milestone for the few women who have ever challenged men at their own game.