Matt Kilroy made his major league debut in 1886 — the season where he lost a league leading thirty-four (34) games.

Even more remarkable is that "losing season" was the same season in which Kilroy struck out a major league record five-hundred thirteen (513) batters, a mark that still stands more than a century after it happened.

In his second season (1887) Kilroy led his league in games won with forty-six (46). The Orioles decided to give his younger brother, Mike Kilroy, an opportunity to pitch and brought him up the following season, but after one game (12 hits & 8 earned runs) they released the younger brother from his contract.