1981-89 Hall-of-Fame METAL PLAQUE #186 Don Drysdale

Team signed baseballs were the thing well before single-signed balls exploded on the market.
What is a "Team Signed Baseball" ???
Simple answer: A ball with XXX signatures of a certain team for a certain year. What is difficult is the XXX. Baseball tons of roster moves make it nearly impossible to "Get Them All".

Generally, team signed baseballs from early 1900's had 10 to 15 signatures, the 1940's that jumped to 18 to 25. Joyce Sports Research Collection (Notre Dame) says "signatures must include only members of a specific team from a specific year, and there must be some approximation of completeness."

Not concrete but to me a "team ball" MUST have ALL the team's STARS (unless a rookie or in season trade) and in today's market at least 20, preferably more, and the manager.

Determining Age of Team Signed Balls
"Official" league balls have stamped signatures of current league presidents on the "sweet spot". Starting 1934/1935 balls were produced by Spalding (NL) and Reach (AL). Rawlings took over in 1977/78. Have a possible team roster at hand, ESPN & baseball-reference.com have great sites), decipher a few signatures then solve the puzzle.