Even if Osuna was only going to throw 100 IP in 2015 had he stayed in the minors, it would have been fine as long as he was an SP for those innings. He was only 20. There was no rush to bring him up and he could have worked on his secondary stuff during that time. Give him 100 IP in 2015, bump that up in 2016, and then maybe by 2017 he would have been a legit rotation option at age 22 if all went well. Worst case, they could have always turned him into a reliever anyway down the road. Now they have no choice. They won't demote him as he's a cheap bullpen piece which they lack, an option of his has already been burned, and his service clock has started. There was no reason to put Osuna in this position. Very short-sighted of AA.
Sanchez is a reliever based on his current skill set, and I think he's a reliever long-term if he doesn't develop a plus 2nd pitch and improve his control, but I'm not that impressed with him as a reliever ATM. Granted, some of that could be because of the way he was used as others have mentioned. Bringing him into games with runners on base and less than 2 outs is basically handing the other team a run since the ball has a high percentage of being put in play. Gibbons being a moron should not be held against Sanchez. However, we're still looking at a guy with a decent/not spectacular K rate and so far a heavy platoon split. Even as a reliever he needs to improve. The potential is there. I just wish he would have spent 2014 and possibly 2015 in the minors as a starter so he maybe could have developed something down there. He has a great fastball and his GB rates are excellent, but he's not a finished product, and unfortunately he may not have time to develop into one given the team's current needs.