Wake Rope Repair?

So I had brought all my gear on a friends (who's a weekend warrior/partier/not frequent wakeboarder) Sea Ray a few seasons ago just incase someone wanted to take a set. I wound up leaving my rope on there. He swore he didn't have it, and it was not on any of the boats I regularly ride so I'd just given up and thought I'd lost it somewhere (which would have been possible cause I ride a lot of different boats).

Two years go by and I'm back on this guy's boat at Lake of the Ozarks and what do I find in the ski locker? He had been using it, which is no problem.... except he put a knot in it and continued to use it rather than untangle it.

It's a MasterLine mainline with the rubberish core and a spectra jacket. The knot is so tight the core is crushed and is squeezing out through the jacket. I don't want to use the line as is, I'm afraid it will snap and get somebody in the boat. Is there a way to cut the knot out and tie the two ends together? What knot would I use? Or should I just scrap it?