Actually, he died in 2013.
Read more:
http://www.baseball-reference.com/bullpen/Walt_Linden
He played for Boston in 1950, hitting .400 in six at-bats.
Linden passed away in September of 2013 at the age of 89, according to a very brief obituary in the Chicago Tribune. The obituary listed neither a place or date of death, or any burial information, making it difficult for researchers to track down the exact circumstances of his passing. One possible clue was that his last place of residence was listed as Western Springs, IL. SABR researchers were able to find the missing information within a few months, however.
http://www.baseball-reference.com/bullpen/Walt_Linden
He played for Boston in 1950, hitting .400 in six at-bats.