So on May 15, 2004, Youkilis belted a home run in his second Major League at-bat. He has been making significant contributions to the Red Sox ever since, though the presence of Mueller did leave Youkilis on the Boston-to-Pawtucket shuttle for two seasons before he found his permanent place in the lineup (first base) in 2006.
Once regarded as the master of plate discipline -- Youkilis was dubbed the "Greek God of Walks" in the best-selling book "Moneyball" -- he has evolved into so much more than that.
Battling it out with Nick Swisher to be the American League's Final Vote candidate for this year's All-Star Game, Youkilis is, well, an all-around star.
At the plate, he not only works pitchers, but when he gets his pitch, he often destroys it. In the field, he is a Gold Glover at first and a highly competent fill-in at third, his old position, when the Sox need help there.
In many ways, Youkilis is a self-made star. Not having the athletic gifts of many of the All-Stars who will make the trip to Anaheim for the Midsummer Classic on July 13, Youkilis never stopped grinding. Even though he's been an All-Star the past two years, not to mention the third-place finisher in the 2008 AL Most Valuable Player Award voting, he continues to find ways to improve.
How did Youkilis get to the point he's at now?
"Just learning about myself," said Youkilis. "You've got to learn your body, you've got to learn every little thing that you do with hitting and fielding and running the bases. It's just going out and trying to better yourself every day and learning the game. There's stuff you can work on every day. You might know a good amount of the game, but at times, you forget little things, and it's all about trying to put all those things together in a split-moment decision too sometimes, with running the bases or fielding."
Where Youkilis was always a good hitter, he is now an ever-dangerous one.
"I didn't know he'd hit for this much power," said manager Terry Francona. "He's such an intelligent hitter, but that's transferred into having a lot of power. I remember when he first came up saying, 'OK, if he hits the ball in the gaps, it'll kind of take care of itself.' But when somebody makes a mistake now, he hits it a long way.
"The biggest adjustment he's made is when he first came up, if a guy had a good slider, it gave him a tough time. You look up now, they make a mistake, he hits it. He's just an intelligent guy that works hard. That year when he was up and down, I remember [Red Sox first-base coach and former Pawtucket manager Ron Johnson] saying he never saw a guy come down and not whine, but try to get better."
When Manny Ramirez was traded to the Dodgers on July 31, 2008, Youkilis slid into the cleanup spot for the Red Sox and has stayed there virtually ever since. It could be a while before he leaves that spot.
Did Youkilis suspect he would emerge into a power hitter?
"I really didn't know," Youkilis said. "I didn't know if I was going to do it or not. Like I said, I just learned how to drive the ball better. I was strong enough. I just didn't know how to use that strength. That was the key. Some guys are strong enough and they don't know how to use that strength. It's all about learning yourself."
Youkilis is one of only four players remaining from both of Boston's most recent World Series championship teams -- 2004 and '07. For all he's done as an individual, what gives Youkilis the most satisfaction is what the Red Sox do as a team. In his first six seasons, Boston has been to the postseason five times. He wants to taste October again this year.
During a grueling stretch in which Jacoby Ellsbury, Josh Beckett, Dustin Pedroia, Victor Martinez and Jason Varitek have all been on the disabled list at the same time, Youkilis has done all he can to keep the Red Sox in contention.
"The whole team thing is what satisfies you as a player," said Youkilis. "It's amazing what we've done battling adversity. To be where we're at right now is remarkable in itself. People put us out of it a long time ago. We've battled back. Even through injuries, we keep winning and doing good things. If we can just keep winning series from here on out in the second half, that will put us in a good chance to make the playoffs, and we'll try to do some good things. Hopefully by then, we'll have all our guys healthy and ready to go."
What has satisfied Youkilis about this first half?
"The main thing it shows is that it doesn't matter as an individual what you've done," said Youkilis. "It's a team game. Not one individual carries a team. Not one individual is going to make or break a season. It takes a whole team. It's not about an individual. There's guys that are going to step up and help out, but it's an overall starting nine and guys on the bench and guys in the 'pen. It's all 25 coming together throughout a whole year. That 25 turns out to be 40 sometimes."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.