Diaz, 26, impressed last season when he posted an .879 OPS and finished fifth in National League Rookie of the Year balloting. This year has been rough on Diaz, as he’s batting .260/.293/.396 with seven home runs and 20 RBI in 288 plate appearances. He’s the second major Cardinals player to get sent down to the minors along with Randal Grichuk.
Diaz was surprised by the demotion. Via MLB.com’s Jenifer Langosch:
Mejia, 26, opened the season with Double-A Springfield but was promoted to Triple-A two weeks ago. With Springfield, he hit .251/.305/.366 in 251 PA. In 42 PA with Memphis, he hit .263/.333/.289.