For instance, check out this great vintage Christmas card available at Legendary Auctions. It is from Jackie Robinson and was mailed to his teammate Gil Hodges. I'll let the auction description detail it for you.
"Dear Gil, It has been a pleasure being a teammate all these years. I hope you have continued success through the years. We expect the day but when it comes it still shocks but that’s baseball. I hope it never comes to you. Give my best to the family. Sincerely Jackie Robinson."
There’s little doubt that this card was sent for the holidays at the close of 1956. After ten years of devoted and very able service, Robinson was coldly dealt away by the Dodgers – to the not-so-prospective New York Giants, it will be remembered. Held in the greatest secrecy, the deal was, like a shot out of a cannon, announced on December 13th. In today’s financial climate, ballplayer esprit is first filtered through the wallet. But in Jackie Robinson’s age, many players genuinely contemplated fealty to their teams … sometimes with measured acceptance, and sometimes with justifiable grumbling. Jackie Robinson’s opportunity in 1947 was, as planned, a sweeping benefit to the game, as well as to the nation’s conscience and self esteem. It was the brainchild of Branch Rickey. But Rickey was muscled out, and the reptilian Walter O’Malley presently directed all the Dodger traffic – and in his fast-moving plans, Robinson had to go. Sure, he was shocked, and it’s a safe bet that Gil was deeply sorrowed (and himself empathetically "shocked") by the … executive decision.