Sitting Youkilis was made a bit easier for manager Terry Francona because the Red Sox are down a starter anyway this week because they can't use the designated hitter in National League parks.
David Ortiz started Thursday's game at first base. Youkilis is expected to start on Friday night against Giants lefty Jonathan Sanchez in the opener of a three-game set at AT&T Park.
"He kind of slept on it," said Red Sox manager Terry Francona. "When I say slept on it, he's having a little bit of a hard time, because he got hit on the nerve -- it's kind of going down his forearm. Since somebody has to sit anyway and there's a lefty going tomorrow, it just seems like it makes some sense to sit him today."
Youkilis, as usual, has been a vital force for the Red Sox this season. He entered Thursday hitting .307 with 14 homers, 47 RBIs and a .430 on-base percentage.
"Again, when you get it on the funny bone, it's kind of black and blue," Francona said. "It's just kind of radiating down his arm a little bit. I just told him yesterday, 'Don't do anything -- let's take advantage of [the rest].' If we're forced to have a guy not play, let's take advantage. If a guy is a little bit beat up, let's give him some downtime."