For me, it was not the trade of specifically Perk that did us in, but it was the fact that Danny traded away half of the team during the mid-season.
Of course, the injuries to Perk, Quis, and Nate probably forced Danny's hand to do something as well as off season financial reasons, but the Gody and Erdin trade to sign Murphy was a total failure no matter how you slice it.
This team was tight. The chemistry of our bench cannot be understated. Nate, as frustrating as he can be, was an awesome guy to have on the bench and brought it a spirit and an energy. Sure, Gody and Semih were rookies and would not have played in the playoffs, but they were the celtic's rookies and having them warming the benches right now would have meant a lot more to them and to the team rather then having a bunch of players other teams didn't want. The fact that three of the new guys have english as a second language probably affects comrodery on the bench as well (I don't mean that in a mean way, but it is true since they are new and language barriers can be an issue when trying build relationships in a short amount of time). We used to have a bench that was fired up at all times, playing or not.
We no longer have that and it does matter to the guys on the court.
We can still win this series. Regardless, for this season, the trades (not just perk but everyone of them) made us a worse team than we were before the deadline.