In the encounter between Yaakov Avinu and the "man", it says (Genesis 32:26):
וַיַּ֗רְא כִּ֣י לֹ֤א יָכֹל֙ ל֔וֹ וַיִּגַּ֖ע בְּכַף־יְרֵכ֑וֹ וַתֵּ֙קַע֙ כַּף־יֶ֣רֶךְ יַעֲקֹ֔ב בְּהֵֽאָבְק֖וֹ עִמּֽוֹ׃
When he saw that he had not prevailed against him, he wrenched Jacob’s hip at its socket, so that the socket of his hip was strained as he wrestled with him.
The Talmud Bavli (Hulin 91a) quotes R' Yehoshua ben Levi:
וריב"ל אמר אמר קרא (בראשית לב, כו) בהאבקו עמו כאדם שחובק את חבירו וידו מגעת לכף ימינו של חבירו
He describes the physical interaction: "(Yaakov Avinu was) like a man who is hugging his fellow, and his hand reached to the "kaf yemino" of his fellow.
Rashi there explains kaf yemino to be referring to some part of the right thigh. This is in accordance with the traditional explanation of the origin for the prohibition of eating the sciatic nerve.
In the chumash Da'at Mikra (page 431 for those with this book available), the explanation on "ויאבק" says as follows:
ויאבק – ...ענינו התגושש. ופרש ר' יוהשע בן לוי: כאיש שחובק את חברו, וידו מגעת לכף ידו של חברו (חולין צא עמוד א). וכן פרש רש"י – מלשון 'אובקו וחובקון'.
According to this citation from the same gemara in Hulin, it is saying that he was grasping the opposite hand of his opponent, not the thigh.
My question is: what is the source of the Da'at mikra which is quoting כף = hand and not thigh? The vilna shas seems not to say this. Does anyone know of other girsa'ot or midrashim that might support the viewpoint cited by Da'at mikra?