The 75-year-old pitcher walked off the field with assistance after collapsing in the relief pitcher's mound.
The president of the team said that he was taken to a hospital after leaving the stadium.
When the episode occurred, Lee was in the right-fieldReliever.
The Bananas play in a collegiate summer league. The club is known for its bright yellow uniforms and entertaining antics on and off the field, and Friday's game was broadcasted on the Disney Channel.
Lee was with Boston and Montreal for over a decade. In 1975, the left-handed pitcher started Game 7 of the World Series for Boston. Boston lost to Cincinnati 4-3 after Lee left the game.
The AP information was used.