I don't have to wonder this, at all. It's actually not even remotely similar. Homer Bailey has had an ERA over 6 each of the past FOUR seasons. An ERA over 5.50 each of the past FIVE seasons. Combined his ERA is over six in those 5 seasons.
His WHIP in those seasons were 1.7, 1.8, 1.7, 1.6 and now 1.5. He has surrendered 12, 13, 11, 12 and 10 hits per 9 innings.
Last year he went 1-14 with a 6.09 ERA. This year he has a 6.05 ERA. ERA's of 6.43 6.65 and 5.56 in the seasons prior.
Nova has been an above average starter his entire career until his sudden struggles in the first half of 2019. Last year he had a 4.19 ERA with a 1.2 WHIP. The year prior a 4.14. The year prior a 4.17. With WHIP's of 1.2 1.2 and 1.2.
Lopez is a young, developing pitcher with coming off a season where he produced a 3.91 ERA and a 1.2 WHIP.
Manny Banuelos is a career minor league pitcher with 13 career Major League starts to his name at age 28. I think everyone realizes he does not belong in a Major League rotation. He has remained in the White Sox rotation due to the extent of injuries endured to the staff and may not for much longer. The White Sox, at no point, came into 2019 with the idea of having Manny Banuelos in the rotation. He is a temporary (albeit extremely inefficient) Band-Aid. He will likely never get another look as an MLB starter again.
Homer Bailey is 33 years old and you can make the argument he has been the single worst pitcher to start in the MLB on an extended basis... every season... for four consecutive seasons. Yet, he was brought into be apart of a Major League rotation. I do not think I need to explain the difference between that and any of the three pitchers you named. Especially Nova and Lopez. For crying out loud. lol