CHICAGO -- Carlos Zambrano is back.

The Cubs starting pitcher hit his first home run of the season and 21st of his career in the fifth inning of Monday night's 14-2 win against the Pirates' Brian Burres.

Zambrano connected on a 1-0 pitch to drive in Koyie Hill. It was his first home run since Aug. 25, 2009, when Big Z connected off the Nationals' Garrett Mock.

Zambrano, who was batting .206 this season with seven hits in 34 at-bats prior to Monday's game, holds the Cubs' record for most home runs by a pitcher. Hall of Famer Fergie Jenkins is second with 13.

Soto day-to-day after MRI on right knee

CHICAGO -- Cubs catcher Geovany Soto underwent an MRI on Monday on his right knee which showed that it was structurally sound but there was some minor swelling. His status was day-to-day.

Soto started during Sunday's 7-5 loss against the Reds and doubled in the eighth inning, sliding head first into second base. He stayed in the game but Cubs manager Mike Quade said the catcher woke up on Monday with some pain. Soto underwent the MRI at Northwestern Memorial Hospital.

Soto said he was able to play with his kids Sunday night and felt a little discomfort. He wanted to have the MRI to make sure there was nothing seriously wrong.

"I have a little bit of fluid that prevents me from straightening it out," Soto said. "It's fine, I'm day-to-day, and hopefully I'll be better tomorrow or the next day."

Teams can expand their rosters on Wednesday, so the Cubs will likely add another catcher at that time. Koyie Hill started on Monday.

Soto was activated from the disabled list one week ago after being sidelined with a sprained ligament in his right shoulder. He batted .250 on the six-game road trip.

Decision on Silva to come after rehab start

CHICAGO -- Cubs pitcher Carlos Silva will make another rehab start on Wednesday for Class A Peoria against Kane County and then the team will make a decision as to whether the right-hander is ready to return to the big leagues.

Silva has not pitched for the Cubs since Aug. 1, when he was pulled after four batters because of an abnormal heart rate. He underwent a cardiac ablation on Aug. 9, and has felt better after each throwing session.

"In the beginning, I was a little anxious, but it felt great," Silva said on Monday about his last rehab outing on Friday in Peoria.

He didn't even think about his heart during the 50-pitch outing.

"I just tried to pitch my game," Silva said. "Hopefully, my next game will be here."

The good outing was a relief for Silva, who used to think his rapid heart rate was caused by adrenaline.

"A lot of people tell you you're going to feel better, you're going to feel more energy, and I felt a lot better," Silva said.