It took me a couple readings to figure out what Nick is talking about (I think the headline is a little misleading...). Anyway, I think the article would have benefited by laying out a hypothetical state of the Twins rotation on March 15th, something like the following scenario:
"Gibson's already-once-repaired UCL blows out again. He is out for the season. Romero's shoulder has been a little sore, so he was shut down early in Spring Training for rest and there is no way for him to build up innings until mid-May at the earliest. The coaching staff is concerned about Pineda's durability coming off basically an entire season off, and really want him in the 5 slot of the rotation so they can regularly skip starts during the first part of the season."
So then, the question is "Does it make sense for the Twins to have a veteran pitcher on a minor league deal in camp?" Personally, I have almost zero faith that Stewart or Gonsalves will be effective big league pitchers, and so I would welcome any additional competition at that tier. Basically:
Pitchers I'm comfortable having in the rotation:
Pitchers that I don't want to have to rely on in any context on Opening Day:
If two or more of the first group are out for whatever reason (injury, performance), then having an additional, veteran arm (or two) in camp on a minor league deal makes sense. More options; higher probability at least one will break out/bounce back.