Wright was taken to Northwestern Memorial Hospital after seemingly suffering from symptoms of appendicitis, but doctors ruled that out late Tuesday and sent Wright back to his hotel. Astros head athletic trainer Nate Lucero and director of research Charlie Norton texted Wade early Wednesday and informed him of the dehydration diagnosis.
"They were concerned about possible appendicitis based on some of the symptoms he was showing and they ruled that out over there [at the hospital]," Wade said. "I talked to [manager Cecil Cooper] this morning, and Wesley was going to hang back at the hotel and just rest up and get himself better."
Wright gave up three runs and walked five batters (one intentionally) in 2 1/3 innings of work Tuesday. He replaced injured starter Roy Oswalt in the second inning and had to warm up on the mound at Wrigley Field.
Wright, a left-hander, is in his third stint with the Astros this year and is 2-1 with a 5.92 ERA in 28 games pitched. He was 1-1 with a 3.94 ERA in 10 games at Round Rock.
"That is big for us," Cooper said. "That means he probably won't be laid up for maybe a day or two, and if it was an appendix, we're talking about a long period of time. Wesley has a great arm and has pitched really good for us, and we need him. Thank God he's going to be OK."
Brian McTaggart is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.