Nava's wife, Rachel, gave birth to daughter Faith on Monday morning.
"She did great and the baby's healthy," Nava said.
Nava can relate to the recent decision of professional golfer Hunter Mahan, who chose to leave a tournament he was leading in order to get home for the birth of a child.
"The birth of your child is something you don't want to miss," Nava said. "You have a lot of respect for someone who leaves a tournament like that when he's ahead. You can get another chance to play, but you only have one chance to be there for the birth of that child."
Nava rejoined the Red Sox having hit .282 with 10 homers and 53 RBIs through 333 at-bats.
"He has been a major contributor all year," Farrell said. "He has put up a lot of good at-bats. He had three days to welcome his daughter into the world and he's back with us now."
Robert Falkoff is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.