Vote: Which Red Sox Player's First-Half Performance Was Most Surprising?Coming into 2012, the Red Sox had a great many unknowns.

How would they respond to the way last season ended? Who on the team would emerge as a leader in the clubhouse without captain Jason Varitek around? How would they react to the new leadership of Bobby Valentine?

Some of those questions may have not been answered yet, but here at the unofficial midpoint of the year, questions about the team's performance on the field have begun to sort themselves out, along with some surprising answers.

The team's bullpen was a large unknown entering this year, compounded even further by the losses of Andrew Bailey to injury, Daniel Bard to the rotation and Mark Melancon to ineffectiveness. In the midst of all that, however, Scott Atchison emerged as one of the most reliable arms out of the pen. The 36-year-old is having a career year for the Sox — as evidenced with his sub-2.00 ERA — and has been a great surprise for the Sox.

Another surprising pitcher, this time in the rotation, has been Felix Doubront. Out of minor league options, Doubront earned a spot in the rotation as the team's No. 5 guy and has been among the league leaders in strikeouts per nine innings while earning his keep on the mound.

The lineup for the Red Sox, meanwhile, has also seen some surprising faces leading the way. Along with David Ortiz's resurgence as one of the most feared hitters in the league, Jarrod Saltalamaccahia has emerged as the best power-hitting catcher in the American League. The two have combined for 39 home runs so far, and they're both showing no signs of slowing down.

And of course, Will Middlebrooks burst onto the scene, and the only thing that's been able to slow him down in his major league time has been injuries.

Which Red Sox player's first-half performance has been the most surprising?