Wasn't Beltrame on the bench in the match against Udinese? He's been training with the senior team regularly recently. Padovan could be injured since I don't think he's ever picked for the first team this season (or rather the Primavera are counting on him).
If Marchisio plays them two will exchange roles a lot during the game, it will be interesting to say the least. As you said his energy is quite good and much needed at times.
The thing I like most about Giacch is that he has impeccable timing with his runs. He always times them from midfield so he has 20meters in front of him to run at, he should play CM.