Scott Eyre, also on the disabled list because of a groin injury, threw one inning for the rookie team at Fitch Park. Among the fans watching the game was Carlos Zambrano, who stopped by the Minor League complex and chatted with the rookie players.
"Lieber and Eyre needed to get the work in, so it was good," Cubs pitching coach Larry Rothschild said.
Lieber, who is 2-3 with a 3.43 ERA in 25 games, has not pitched since July 11, while Eyre, 2-0 with a 4.91 ERA in 18 games, has been out since June 27.
On Wednesday, Kerry Wood may throw if the blister on his right hand has healed. He has not been in a game since July 11, and saw a hand specialist on Monday in Phoenix.
"It's day to day, and we'll see how it reacts," Rothschild said of Wood, the Cubs closer who has 24 saves in 29 opportunities.
Newly acquired starter Rich Harden threw 112 pitches Monday in his second start for the Cubs, and Rothschild said they will keep an eye on his pitch count in his next outing Saturday against the Florida Marlins.
"We're trying to keep from extending him too much," Rothschild said. "We'll have our eyes open on that one, and we'll see the next start if we need to shorten him up."
Rothschild and Cubs assistant general manager Randy Bush also watched Angel Guzman throw a simulated game Tuesday at Fitch Park. Guzman is rehabbing from Tommy John elbow reconstruction surgery on his right elbow last year.
"With Guzman, the one thing with a guy who has been injured that much is you look for the arm strength, and it was there," Rothschild said. "He threw the ball with real good velocity, and he seems to be on his way."
Guzman has been throwing simulated games in Mesa for about six weeks. The Cubs want to see how his arm feels Wednesday before making a decision on the next step in his rehab.
"He's been throwing mostly sim games, but hadn't been throwing breaking balls until the last few weeks," Rothschild said. "He's getting close to going out [to a Minor League team]."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.