#4 Rhett Kouba
Rhett Kouba isn't a household name, but he could be a key cog moving forward. Kouba won't win a Cy Young, but José Urquidy has made quite a living for himself eating innings while Justin Verlander wins Cy Youngs. Again, the Astros were desperate for depth last year. Kouba's fastball/changeup combo and ability to pound the zone (2.7 BB9 in his minor league career) gives him an eerily similar profile to Urquidy.
In 28 appearances across AA and AAA, Kouba posted a 3.45 ERA and 1.20 WHIP, striking out 136 batters in 128 innings.
Unless disaster strikes, the Astros should get Lance McCullers Jr. back in 2024, and Luis Garcia could make a return late in the season. If Houston takes the same risk they did last offseason and decides not to sign any starters, Kouba could be their bet as a spot starter to bridge the gap to the returns of McCullers and Garcia.
A rotation of Verlander, Valdez, Javier, Brown, McCullers and Garcia is still incredibly formidable and would provide plenty of rest to keep arms from wearing down. If the Astros decide to spent outside of their pitching knowing they have an elite rotation of six arms when healthy, Kouba could be a big part of why.