[Mick]

I watched a truncated replay of Matt Cain's perfect game, and Chris Heston's no-hitter. Heston's career record was 13-13, and he threw a no no. Old timers might remember Ed Halicki, owner of a 55-66 record, who threw a no hitter. Most of the Giants' pitchers who threw no-hitters are very well recognized (Mathewson, Marquard, Hubbell, Rusie, Marichal, Wiltse, Tesreau, Barnes, LIncecum, Cain, Montefusco, Perry).

Who was the worst pitcher to ever throw a no-hitter? Who was the worst to throw a perfect game?

Conversely, who were the best pitchers to never throw a no-hitter (minimum, 200 wins)?

I was at the Ed Halicki no-no (v. the Mets).  There was a controversial official scorer’s ruling on a ball hit to Felix Millian.  He made a nice stop but couldn’t complete the play.  It was close enough to rule an error.  

Len Barker “worst” to throw a perfecto?

It's debatable, but I'd go with Charley Robertson. Robertson's perfect game was only his fifth appearance, and fourth start, in the big leagues. He finished his career with a 49–80 record, the fewest wins of any perfect-game pitcher until Dallas Braden (26-36 overall). Robertson's winning percentage of . 380 remains the lowest of anyone who ever threw a perfect game. Braden at least had one winning season, Robertson never had a winning season.

https://jacobpomrenke.com/black-sox/apri...fect-game/

What would baseball be without controversy?

Worst pitcher to throw a no-hitter was likely Bobo Holloman. He was only in the majors for a year, 1953, with a terrible team, the St. Louis Browns. His record that season was 3-7. That's right, he had three wins in his entire career and one of them was a no-hitter.

He beat the A's, 6-0, on May 6, 1953. And the A's weren't sad sacks, they had some very good hitters...Dave Philley hit .303 for the season, Gus Zernial had 42 HRs, Eddie Joost had an OBP of .401, Ray Murray hit .284, Eddie Robinson had 22 HRs. 
Philadelphia Athletics vs St. Louis Browns Box Score: May 6, 1953 | Baseball-Reference.com

So...Clemens never had a no-hitter. Grover Cleveland, with 373 wins and 90 shutouts never had a no hitter. Robin Roberts, Curt Schilling, Fergie Jenkins, Mike Mussina, Pedro Martinez, Steve Carlton and Greg Maddux never had no-hitters. But Bobo Holloman, owner of a lifetime 3-7 MLB record, has a no hitter.

[Mick]

I watched a truncated replay of Matt Cain's perfect game, and Chris Heston's no-hitter. Heston's career record was 13-13, and he threw a no no. Old timers might remember Ed Halicki, owner of a 55-66 record, who threw a no hitter. Most of the Giants' pitchers who threw no-hitters are very well recognized (Mathewson, Marquard, Hubbell, Rusie, Marichal, Wiltse, Tesreau, Barnes, LIncecum, Cain, Montefusco, Perry).

Who was the worst pitcher to ever throw a no-hitter? Who was the worst to throw a perfect game?

Conversely, who were the best pitchers to never throw a no-hitter (minimum, 200 wins)?

I was at the Ed Halicki no-no (v. the Mets).  There was a controversial official scorer’s ruling on a ball hit to Felix Millian.  He made a nice stop but couldn’t complete the play.  It was close enough to rule an error.  

Len Barker “worst” to throw a perfecto?

It's debatable, but I'd go with Charley Robertson. Robertson's perfect game was only his fifth appearance, and fourth start, in the big leagues. He finished his career with a 49–80 record, the fewest wins of any perfect-game pitcher until Dallas Braden (26-36 overall). Robertson's winning percentage of . 380 remains the lowest of anyone who ever threw a perfect game. Braden at least had one winning season, Robertson never had a winning season.

https://jacobpomrenke.com/black-sox/apri...fect-game/

What would baseball be without controversy?

Worst pitcher to throw a no-hitter was likely Bobo Holloman. He was only in the majors for a year, 1953, with a terrible team, the St. Louis Browns. His record that season was 3-7. That's right, he had three wins in his entire career and one of them was a no-hitter.

He beat the A's, 6-0, on May 6, 1953. And the A's weren't sad sacks, they had some very good hitters...Dave Philley hit .303 for the season, Gus Zernial had 42 HRs, Eddie Joost had an OBP of .401, Ray Murray hit .284, Eddie Robinson had 22 HRs. 
Philadelphia Athletics vs St. Louis Browns Box Score: May 6, 1953 | Baseball-Reference.com

So...Clemens never had a no-hitter. Grover Cleveland, with 373 wins and 90 shutouts never had a no hitter. Robin Roberts, Curt Schilling, Fergie Jenkins, Mike Mussina, Pedro Martinez, Steve Carlton and Greg Maddux never had no-hitters. But Bobo Holloman, owner of a lifetime 3-7 MLB record, has a no hitter.