After spending the first five years of his professional career in the Philadelphia Phillies Minor League system between 1965 and 1969, Rounsaville was drafted by Chicago in the Rule 5 Draft before the 1970 season.
He’d make his Big League debut on April 7th and spend the month with the White Sox, going 0-1 with a bloated 9.95 ERA over those eight games, throwing 6.1 innings all out of the bullpen.
He would spend the rest of the year in the Minors, pitching well to the tune of a 3.26 ERA over 27 appearances and 91 innings, with five saves.
However from what I can find, he never played pro ball again, even though he was still only 25 years of age, finishing up with those eight Major League appearances and a record of 0-1.