It's Spring Training, Charlie Brown (1996)

As springtime rolls around, Charlie Brown's team is performing the usual hopeless task of getting in shape for the new season. To improve the team's morale, Charlie Brown manages to find a potential team sponsor who agrees to provide uniforms, provided that the team wins the first game of the season. However, considering the usual competence of the team, including new members like Leland who is too young to even tie his shoes, the challenge seems impossible.