In our opinion, one of the most underrated Pitchers that ever existed has to be Billy Pierce, who was a seven-time All-Star and five-time leader in bWAR with the White Sox.
Regardless of the era, it is an impressive feat to be a key member of Chicago's rotation for a decade. The Chicago White Sox may not have won a World Series in the ’50s, but they were a good team and much of the success they did have, was through a big part of the pitching of Billy Pierce.