They got mad at Corpas for blowing 3 straight saves. Corpas is the must better bet for long term success but Fuentes is still a very nice closer and a must pickup in all leagues.
Corpas is the closer of the future but he can't get an out right now and Fuentes is dealing. I'd expect Fuentes to keep the job for at least half the season if not the entire thing. Corpas has a ton of value in a keeper league but he is struggling and Fuenets is capitalizing. You should be safe to drop him as no one else will be interested more than likely. Just keep an eye on the situation if anything changes, but for the next month or two it should be all Fuentes.