Not worth much until it's cut and dried. Pretty much firewood until then. Sawmills won't deal with one tree. Try to locate someone with a portable sawmill to cut it for you, air dry it for a few years, hope the insects don't get to it and you might make a few bucks.
Many years ago I had cut up an English Walnut tree and took it to an old farmer to cut it up on his saw mill in his barn. I painted the edges to prevent checking. and forgot all about it. About 6 years later a old gentleman friend said in passing that he was looking for some walnut to make a stock for his son. I showed him this wood and he flipped. I gave him his pick, begging me to take money I said NO. Being the good friend that he is and an excellent craftsmen. He made me the sweetest Banjo you'd ever lay your eyes on. Since that day I sold all 11 blanks for an ave. of $300.00. I presently have two trees being cut again. But they are years away from being near ready.
The tree is in good shape. It was removed because of where it was at not because of anything wrong with it. It is about two feet in diameter and the longest piece is about 10 feet long to the shortest about 4 feet long.
Right now walnut wood sales are quiet good , My friend is getting ready to harvet about 450 acres and most is sold already. A lot will go for veneer out of the burrels and then there is the block wood, the special wood will go in the drying blocks for stocks and mucical insterments, and flooring. So if you can get it sawed up might be worth something.