According to this blog post:
Thursday, March 29, at about 2:00 p.m, central time, Ria Cortesio will step into position on the first base line in Phoenix, Arizona, and she will do something that no woman has done since March 1989. She will be an umpire in a game between major league teams (if you count the Chicago Cubs as a major league team).
I write because Ria is a friend of mine. She’s someone that I’ve known since the 1990s when she was a student at Rice University, and she was working as part of the Astrodome video crew.
She’s been working at this for a long time, now. In Houston, she umpired high school and little league games. She’s umpired in the independent leagues, she spent time in A-ball, and she’s about to start her 5th year with the AA Southern League. She’s been accused by George Steinbrenner of squeezing the strike zone on Roger Clemens — this was during a Clemens rehad start in Single A ball. She also happens to be the next in line to advance to AAA.
Good luck, Ria. I’m pulling for you to make the majors. But just don’t expect me to pull my punches. The umpire always sucks.
More here. Somebody better tell Keith Hernandez to take deep cleansing breaths!