Kenta had an 11 game stretch, starting in mid June up to the game he was injured, where he looked exactly like the pitcher most assumed he would be. If you want to assign his rough 5-6 game stretch in May/early June to injury, fine, but that's digging into the weeds of how often players are taking the field at 100%, and it's a discussion outside of the point I'm making. Pineda skipped a single start in May, went on the IL in mid June, and was back pitching by early July. At any given time from opening day through the trade deadline this team had 4 or all five of the opening day rotation members available to pitch assuming Shoemaker wouldn't have completely imploded.
We see the depth very differently. Dobnak was coming off a year in which he was demoted, and he clearly was first in line to get starts when/if needed. He was flat out terrible, and I'm soooo tired of the usage defense. Thorpe wasn't good in either '19 or '20 with the Twins; Idk what the expectation was there. Smeltzer is the WC, but damn, if that's your first line of defense for supplementing the rotation.....yikes. The kids weren't likely to be a factor until midseason at the earliest, and by then the damage was done. I'm not blaming the FO for injuries either, they obviously have zero control there. I'm saying that tallying them up in late in September isn't painting an accurate picture.