Meghan Markle's Yoga Mom is Now Frontrunner to Walk Daughter Down the Aisle

Meghan Markle's mom may have to make a quick transformation -- both in apparel and location -- because she's now the leading candidate to walk her daughter down the aisle.

Doria Ragland was going about her business in L.A. Monday, just 5 days before her daughter gets hitched to Prince Harry. The yoga instructor has been keeping a low profile, but that's about to change.

TMZ broke the story ... Doria's ex-husband, Thomas Markle, was supposed to give Meghan away, but he tells TMZ he's no longer going to the wedding because of the photo scandal. He made a deal with a paparazzi agency for some photo ops in return for cash, and the story presumably pissed off the Royals.

Thomas says he wanted to go to the wedding so badly ... he left the hospital prematurely after suffering a heart attack just 6 days ago because he wanted to attend the nuptials.

No official word on who will be substituting for Thomas, but we're sure it's not her half sister, so our money's on Doria.