Doesn't look like Radicchio to me. Maybe Oakleaf Lettuce....but that's a guess.

I agree with Kate. Does not look like radicchio to me.

hmm how about turnip greens (seven top) ? it's kind of pale green though..If you look at the new growth the leaf pattern appears to be changing from more serrated to smooth. this was planted in the fall, so i don't know if it will seed this year if it's a biennial.. don't think it's lettuce at all. hope to find out soon..

I would guess a radish of sorts but turnips would be very reasonable.

Looks like the Turnip Greens, or maybe just a weed. Doesn't look anything like Radicchio.

I think it does look like a chicory, Cichorium intybus. This species has been developed into many cultivated forms, including Radicchios, which occasionally throw up random genetic throwbacks to the wild species. I’ll bet it bleeds a white sap if torn, which eliminates anything in the Brassicaceae, including turnip and radish.