This is a 1951 all star game autographed baseball. There are 15 Hall of Famers on this ball and also includes a rare autograph from Gil Hodges. Ty Cobb threw out the ceremonial first pitch in this game and is the reason he is on this baseball. Other Hall of Famers include Jackie Robinson, Ted Williams, Stan Musial, Yogi Berra, and 10 others you can see on the LOA. This is the only item I have come across that has been signed by both Cobb and Jackie Robinson.
 
This is fully authenticated by JSA.