Donaldson's situation is a Catch-22. If he goes hard on every play, it's more than likely he will pull his calf muscle again. If he doesn't, he looks like he's not trying. The Twins didn't sign Donaldson so that they could claim third place in the Central, so his signing looks like a colossal waste.
Simmons is pretty much as advertised. The only thing surprising to me is the lack of leg speed when running the bases. He doesn't have a gun for an arm, but neither did the all-time greatest defensive shortstop, Ozzie Smith.
Happ and Shoemaker both have had good and bad outings. They need to have good command and if they're off by much, they'll get hit hard. It seems that each guy got two starts against their worst possible matchup (Happ vs. White Sox, Shoemaker vs. Athletics) and they both got knocked around pretty hard. A team looking to make postseason might take a chance on either as long as they're healthy.
What about Cruz? He's only a DH and he's been insanely productive for the Twins, but he'll be 41 in just over two months and he has slipped some this month. I don't think he's part of the Twins future, so regrettably maybe he should be moved, as well.