Fiorentina decline started in their last 6 or 7 games just as you have said, earlier on in the season, they were doing well but declined all of a sudden, maybe their squad depth isn't enough to stay at the very top in which they had planned to, maybe fatigue has set in for the players and they are tired that's why they have this sudden decline in form which has been affecting their recent run of form.
Not having good squad depth makes it difficult for a team to defend at their best and it is very problematic if some of the key players get injured. Fiorentina have been facing a decline in performance so far and they have really struggled to get a win in the last six games. For the next few games Fiorentina will face slightly stronger opponents so it will be difficult for them to get the three points. For the match against Torino they have to be able to get the three points because the next match will be against Lazio. It seems that it will be a little bit more difficult for Fiorentina this month because they will face much tougher competition.