I think I was unclear about what my plans were. I meant that if the yarn would felt, I had intended on felting the sweater, then cutting pieces out of the then-felted wool, and sewing something from it.
It's all a moot point, anyway. My dh saw the sweater and really liked it. To think, I came so close to tossing it into the washer today.
I didn't think he'd want it because it's so scratchy; plus it's an XL, and he normally wears a L. He tried it on, and wearing it over a shirt it will fit him nicely.
Thanks everyone for your advice, anyway. :D