Cubs pitching coach Larry Rothschild said the early session went well.
"He progressed from the last throwing session, which is good," Rothschild said.
The right-hander will have Monday off, then throw a light side, then another batting practice session. Prior's velocity is improving each time as well.
"He's getting close," Rothschild said. "I wouldn't say full velocity from what you've seen a couple years ago, but it's a definite improvement. He's handled the work load with flying colors."
Prior has said he expects to be ready by Opening Day of the regular season.
"I have no indication that he won't be [ready]," Rothschild said.
"We're going to make sure he really feels that he's ready," Piniella said of Prior. "There's no sense in rushing that situation. I would think that by the following Wednesday or Thursday, we'll get him in a ballgame."
Mark March 7-8 on your calendar. Wood, being groomed for the bullpen after spending the winter rehabbing his right shoulder, faced hitters Saturday for the first time, and was slightly behind the other pitchers. All indications are that both are doing well. The Cubs know that because Prior isn't on Rothschild's list for the first five games, it could be interpreted that he's had a setback. That's not true.
"This is precaution, and nothing more and nothing else," Piniella said. "We want to keep it positive. We want to see some small but steady progress. You rush something and all of a sudden you have to stop it and set it back and you lose double the time."
Piniella missed Prior's throwing session.
"I went to chapel, so I didn't see it," he said.
As for the rest of the starting pitchers, the Cubs' Cactus League rotation will be Jason Marquis on Thursday against the Giants, followed by Carlos Zambrano on Friday vs. the Angels, then Wade Miller Saturday against the Athletics, and Rich Hill on Sunday against the White Sox. Former Notre Dame wide receiver turned pitcher Jeff Samardzija was on the list to pitch Saturday as well.
Ted Lilly, the other addition to the Cubs rotation, will start March 5 against Seattle.