[Mick]

Mel Stottlemyre, yes. 12-20 for the 1966 Yankees, led the league in losses, also led the league in losses six years later when he went 16-18. But he won 20 games three other years, finishing 164-139. So the man could pitch.

Here's the rest of the pitchers who both lost 20 games and made the All-Star team that year...and whether they actually pitched in the game. Raffensberger actually won the All Star game in 1944:

Pitcher           Year   Team                  W–L  Pitched in All-Star Game?
Hugh Mulcahy      1940   Phillies             13–22      No
Eddie Smith       1942   White Sox             7–20      No
Ken Raffensberger 1944   Phillies             13–20     Yes
Bob Rush          1950   Cubs                 13–20      No
Sam Jones         1955   Cubs                 14–20     Yes
Turk Farrell      1962   Houston Colt .45s    10–20     Yes
Mel Stottlemyre   1966   Yankees              12–20     Yes
Steve Rogers      1974   Expos                15–22      No

[Mick]

Mel Stottlemyre, yes. 12-20 for the 1966 Yankees, led the league in losses, also led the league in losses six years later when he went 16-18. But he won 20 games three other years, finishing 164-139. So the man could pitch.

Here's the rest of the pitchers who both lost 20 games and made the All-Star team that year...and whether they actually pitched in the game. Raffensberger actually won the All Star game in 1944:

Pitcher           Year   Team                  W–L  Pitched in All-Star Game?
Hugh Mulcahy      1940   Phillies             13–22      No
Eddie Smith       1942   White Sox             7–20      No
Ken Raffensberger 1944   Phillies             13–20     Yes
Bob Rush          1950   Cubs                 13–20      No
Sam Jones         1955   Cubs                 14–20     Yes
Turk Farrell      1962   Houston Colt .45s    10–20     Yes
Mel Stottlemyre   1966   Yankees              12–20     Yes
Steve Rogers      1974   Expos                15–22      No