Jennifer Lopez Wishful Thinking?

3/18/2017 1:45 PM PDT

Alex Rodriguez's Sister Called Jennifer Lopez Her Sister-In-law

It seems Alex Rodriguez's sister has already decided Jennifer Lopez is the one for him ... cuz she posted a pic with the singer and claimed her as a member of the family. 

A-Rod's sis, Susy Dunand, posted a couple pics with J Lo Friday ... but it was her caption that raised eyebrows, using "#miscuñis" -- the Spanish word for "sister-in-law" -- in the post.

There is, however, a chance Susy was referring to the other woman the pair was hanging with ... but either way, family intros are a big deal.