Dog lovers will appreciate this ... New York Mets catcher Tomas Nido just showed major love to his adorable pup -- by getting a tattoo of the canine on his leg!
TMZ Sports has learned the baseball player wanted to get some ink to celebrate his beloved pet last week ... so he hit up artist Keith Hernandez from Bang Bang Tattoo in New York City.
We're told the 27-year-old handed over a portrait of his Yorkie, Louie, that he got 8 years ago .