McLain pitched 336 innings that year and had 28 complete games. I don’t know how many cortisone shots he got that year, but that’s what kept him going. McLain had another very good year in 1969, but after that his arm was shot.
Complete games by a starting pitcher are a rarity now. Most starters are limited to 100 pitches/game now. Kershaw pitched a great game last night, but was yanked after 8 innings. Had he pitched the 9th he may have a gotten a complete game shutout.
The last of the complete game / use him as much you need him pitcher I believe was Orel Hershiser for the Dodgers late 80s championship. He started repeatedly on short rest, pitched long, and was even used in relief in the same series against the Mets and A’s.