Defender Chris Schuler is out with an injured foot, while midfielder Sebastian Velasquez has turf toe on his right foot.
Also, while still on the field, defender Jamison Olave is not 100 percent with a right calf strain.
"I think everybody can see it's affecting him," Kreis said.
Midfielder Javier Morales is slowly rebuilding his conditioning from a right quad strain so he can go a full 90 minutes. He came off the bench in the second half in two games prior to Saturday.
Midfielder Luis Gil also suffered a small injury a right knee strain he picked up at the U.S. Under-20 national team camp. He was able to come off the bench for the final 26 minutes of Wednesday's 3-2 loss to the Los Angeles Galaxy.
"It felt good, especially getting back on the field so quickly," Gil said. "I feel like I've got to get back into that rhythm, though. Obviously, time off takes that away and you feel a little slow; just getting back into the soccer rhythm, getting back on the ball, more confidence."