The actor said that he is "excited" for his character Manny to have a new half-sibling in season four after it was revealed in the finale that his mother is expecting a baby with new husband Jay (Ed O'Neill).
"I'm so excited. I didn't even know about it, so my jaw dropped when I was watching it," E! quotes him as saying. "I was like, 'Wait a minute, what?' It was a crazy finale."
Asked whether he'd like a brother or sister for Manny, Rodriguez replied: "Twins, that would be cool, but hopefully they go for a boy."
Cheryl Cole has been tipped for a guest appearance in Modern Family's fourth season, while Britney Spears has spoken of her desire to land a cameo.
Reports suggest that the main cast are looking for a pay rise of $135,000 (£85,000) per episode for next season.