Diaz left Sunday's game when he hit the side of first base while trying to avoid a collision with Rays pitcher Chris Archer on an infield single.
The Blue Jays said that backup infielder Lourdes Gurriel Jr. will start at short in Diaz's absence.
"From what I've seen, I think he's more comfortable at short right now, and I'm talking about because of the throw, he likes to cut it loose," Blue Jays manager John Gibbons told MLB.com. "The throw from second, he has a good arm, and I think the distance has kind of messed with him a little bit, cutting the ball loose."
Gurriel, 24, is hitting .236 in 16 games with two home runs and seven RBIs.
Diaz, who took over at short for the injured Troy Tulowitzki, was hitting .216 with six home runs and 13 RBIs on the season.