Vintage Game Used Baseball Help
 

I picked this one up recently... The seller was selling off many items for his Daughter in Law's Grandfather who owned a bar in Pennsylvania... The Grandfather apparently caught this ball at a Phillies game on the date inscribed on the North Panel:

5/21/1952- Phillies beat the rival Bucs 7-3. Robin Roberts pitched a complete game to notch his 7th victory on the season (70th career). 1952 was a very impressive season for Robin (likely the best in his career)... (28-7 W/L, 2.59 ERA)

http://www.baseball-almanac.com/box-...d=195205210PHI

Does anyone have any idea as to what something like this would be worth? and likewise if there is anyone Phillies/Roberts fans who are interested i am totally open to trading/selling it... I would like the ball to find its way into a collection where it will be appreciated.

Thanks!
Dave