Tammy and her best friend Andrea had just begun elementary school and joined the soccer team, with the coach, Emma Putter, who had just moved from England with her family.
Tammy and Andrea had started their first year at junior high, and they struggled to find an activity to join before both settle on trying out for the baseball team. She is a natural, but Andrea struggles at catching and hitting, running the risk of being cut altogether until Tammy, without Andrea's knowledge, convinces Coach Crenshaw that her and Andrea are best friends and if Andrea is cut, she won't play either. When Andrea is benched for most of the season, Tammy leads the team and then becomes the catcher for most of the season until Randy accidentally hits her in the right elbow with a wild ball causing an injury, leaving her unable to play and Andrea replaces her.
When Andrea struggled on the team, she overheard Tammy confessing to Randy the deal she made with Crenshaw when Randy wondered why Andrea was on the team even though she stinks. On the day of the championship game, Carlton and Professor Siles kidnapped Buddy, with Tammy and Andrea in pursuit, rescuing Buddy, Zack, Striker, Shooter, and Duke before experiments could be conducted on them. The Timberwolves struggled without their three-star players, but they managed to come back from behind to edge out their rivals, the Baboons, in an 8-7 game, when Andrea hit a home run.
School was out for the summer and Tammy was sad about moving to California because she would miss her best friend. On their last night together, they had a sleepover in a tent and gave each other gifts. On the day of moving, Tammy sadly said goodbye to Andrea, Buddy, and her family.
The next morning, Andrea felt a lot better and happy that Tammy sent her a postcard, having invited her to California.