Tomas experienced nausea and was dehydrated Tuesday. He had experienced similar problems the first time the D-backs visited Denver earlier this year.
Tomas said he felt better after receiving some medicine Tuesday night.
• Right-hander Archie Bradley (shoulder tendinitis) made a rehab start for Triple-A Reno on Wednesday, allowing three runs on six hits while striking out three over four innings. He will make another start five days later before the team decides whether he is ready to come off the disabled list.
Even if he is healthy, D-backs manager Chip Hale reiterated that Bradley will have to pitch well if he wants to reclaim his spot in the rotation.
• Left-hander Patrick Corbin (Tommy John surgery) was set to pitch for Double-A Mobile on Wednesday. Corbin will likely make one more start before the team decides whether to activate him.
If both pitchers come off the DL it could make for a crowded rotation.
"We've got a lot of decisions to make, don't we?" Hale said.
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.