I have always been under the impression that Blanda was the oldest man to ever play in the NFL. Played till he was 48 I think. Quarterback early and then switched to kicker for the Raiders in the 70's.

I was looking at pro-football-reference.com and the 1933 Pittsburgh team (Pirates) has two guys listed as being 63 years old. One of them, James Clark, had 76 carries for 192 yards. He played again the next year as a 64 year old. I just checked Blanda and his last season was 1975 and he was 48. I don't see any listing there of oldest players ever. I will investigate further.