However, Wood ended his bullpen session on Thursday early because of some tightness on his right side under his arm, but Rothschild said he didn't think the problem was too serious.
Rothschild said the Cubs took a cautious approach when Wood complained of the problem while warming up. The right-hander, who also is rehabbing in Mesa, was to face some Minor League players.
"He didn't feel all the way right with it," Rothschild said. "He thought it would be better not to throw in the game after he got warmed up.
"If he pulls something, even though it's not the spot where we're concentrating on, it could set him back too far," Rothschild said. "We probably did the right thing."
Wood is coming back from arthroscopic surgery on his right shoulder, which he underwent last August. The latest tightness was not in the area where he had the surgery. Wood has been pitching in controlled situations, not real games yet.
Wood received treatment on Friday and will try to throw a side session on Saturday. If there's any problem, his next simulated game will be pushed back, Rothschild said.
"It may be one time around the rotation that he's set back, but hopefully that's the way it works out," Rothschild said.
Wood also may have been bothered by the news that his former pitching coach, Oscar Acosta, was killed in a car crash in the Dominican Republic.
Cubs manager Dusty Baker said he had heard that Wood was "a little distraught" at the news about Acosta, who was the team's pitching coach from 2000-01.
"They were real close," Baker said. "It's understandable."
The Cubs also made a move regarding pitcher Wade Miller. He is rehabbing from the same shoulder surgery Wood had, only Miller's was in late September. The Cubs switched Miller from the 15-day disabled list to the 60-day to make room on the 40-man roster for Michael Restovich, who was called up from Triple-A Iowa to take Derrek Lee's place.
"We sketched out his schedule and we're looking at the first of June," Rothschild said of Miller's tentative return date. "That was a decision that was not tough to make. I talked to Wade [on Thursday night] and told him what the situation was and he understood perfectly. It's hopefully going to be close to the first [of June]."