Theodore was an odd-looking rookie in 1973 for the New York Mets, who went by the nickname of "The Stork" because of his long, lanky, funny appearance. he He was a fourth outfielder and occasional pinch-hitter for Yogi Berra in '73 until he suffered a serious injury to his hip when he collided with Don Hahn on July 7th. The Stork missed more than two months and appeared in only one game in September before the regular season ended. Still, the Mets carried him on their World Series roster and he appeared twice in the Fall Classic as a pinch-hitter, though he failed to produce a hit. In 1974, Theodore served almost solely as a pinch-hitter for the Mets but he hit only .158 and never played in the majors again after that season.