You have to be a good pitcher to lose 20 games in a season. A bad pitcher would get sent to the minors or released long before they lost 20 games. A good one would be kept around because management knows he can still pitch effectively despite the worst efforts of the rest of the team.
Then again, you have Steve Carlton in 1972.
The Phillies won 59 games.
Steve Carlton won 27 of them. 😇
That year he started 48 games. completed 21 and threw 359 innings. iron man stuff.
some guys have been in the majors 10 years and haven’t threw that many pitches.
Ryan Brasier,(reliever) 9 years, 311.1 innings lifetime
same team, same year Stan Bahnsen went 18-21...yikes.