Flacco's wife, Dana, gave birth to a baby boy around noon ET, according to a team spokesman. She was due on Sept. 21, but she went into labor Sunday morning.
After warmups, Flacco received a call in the locker room from his wife after their second son was born. Their first son, Stephen Vincent, is 15 months old.
Flacco, the MVP of Super Bowl XLVII, will play today against the Browns.