Got the Nats broadcast here. Fabulous insight from Don Sutton about Redding's career as an Astro.
The problem with Timah's four seamer approach with curveball is that he would exhaust his pitches trying so hard to strike everyone out that he would just barely make it to the fifth inning. A major leaguer who you feed four seamers all the time will simply foul the ball off. So what Timah was used to throwing in AA and AAA to strike out guys was basically a foul ball pitch in the majors. In essence, if you're just going to pitch north in the zone and ignore the south, that eliminates one part of the plate for the hitter. Major leaguers will simply foul balls away high in the zone until you bring it down and then they explode on your pitch. That pretty much makes the curveball a pitch you spit on. A sinkerball or two seamer makes it easier for you to pitch south with your fastball and also will help you maintain quick innings instead of 20-25 pitch innings. Jason Hirsh, for example, learned how to pitch effectively in the minor using the four seamer, changeup and sinker ball. He had short innings because minor leaguers would try to square his sinkerball and just when they were not expecting it, he would bust them upstairs. Hirsh is a much more polished pitcher coming into the majors than Redding was when he came up.
There is a difference between pitching and throwing.
For example, Roy Oswalt was a four seamer/curveball pitcher like Redding in AA. He was taught by Pitching Coach Maddux the value of going ahead and having shorter pitch counts per inning by using a sinkerball. To this day, Oswalt will tell you that this changed his approach and prepared him to be a major leaguer. It worked for Oswalt and Redding did not listen to Maddux who tried to help him do the same. Redding had more talent than Oswalt in the minors, but he was striking out guys in the minors with his four seamer while Oswalt was learning how to be a major leaguer. By the time Redding came up to the majors, he was getting gassed by the fourth inning with pitch counts in the high 80s and 90s... four freaking innings is all he could manage because that four seamer that was unhittable in the minors became a pitch major leaguers just simply wasted until Timah threw it over the plate.
So while Sutton is correct what the Astros tried to do with Redding, he's wrong about it being the Astros who were (implied) incorrect in that approach. Oswalt is exhibit A that it's a very sound approach. Redding merely exhibited a stubborn nature about it all and he has no one but himself to blame for his less than Oswaltian rise to the major leagues.