Middlebrooks and Nava, former teammates at Triple-A Pawtucket, have kept the Red Sox afloat through an array of injuries since joining the club in early May.
A fifth-round pick in 2007, Middlebrooks hit safely in 21 of his first 25 games since being recalled from Triple-A on May 2.
Undrafted out of college, Nava spent parts of seven years in the Red Sox's farm system and wasn't invited to Spring Training this year. But he's found a home in left field since being recalled on May 10, starting there in his first 25 games and reaching base in 23 of those contests.
The Red Sox wrapped up the 2012 First-Year Player Draft on Wednesday and will soon begin filling their Minor League system with fresh faces and new prospects.
So who could be the next Sox farmhand to make an impact in the big leagues in the not so distant future?
A first-round pick in 2010, Bryce Brentz is Boston's No. 2 prospect (behind Middlebrooks) and showing signs of becoming a power hitter. In 52 games for Double-A Salem this year, Bentz is hitting .300 with seven homers, 13 doubles and 20 RBIs.
"He's really turned himself into a really good hitter with raw power," said amateur scouting director Amiel Sawdaye. "He's hit a lot of home runs and definitely progressed really well and we're really excited about him."
Brentz also totaled 30 homers and 94 RBIs last season between Class A Salem and Class A Greenville.
As for pitchers, 2011 first-round pick Matt Barnes has flashed all the tools of a dominant starter.
The University of Connecticut product is 5-1 with a 1.59 ERA in 11 starts between Salem and Greenville this year. He has 81 strikeouts in 60 2/3 innings with just eight walks.
"He's having a really good year," Sawdaye said. "He's progressing really well. As much as he's had a lot of very significant strides and been successful, he's still developing. With any young pitcher it's about consistency, delivery, repeating pitches, learning how to pitch. We're just kind of continuing to stash that in his mind. The more he gets out there and throws and the more innings he throws the better he'll be."
At 6-foot-4 and 205 pounds, Barnes looks the part of a future frontline starter. His fastball reaches 96 mph and he maintains his velocity deep into his starts. He's developing a plus curve and already has a solid changeup. As he continues to master his command, look for him to rise through the Minors.
Brentz and Barnes are some of Boston's highest picks over the past five Drafts. Here's a glance at other notable selections and where they're at in the Red Sox's pipeline:
From the 2010 Draft
Anthony Ranaudo, RHP: Taken with the 39th overall pick two summers ago, Ranaudo has overcome a slew of injuries and has three above-average pitches: a fastball, curve and changeup. He joined Double-A Portland in mid-May and is 1-1 in four starts with 14 strikeouts in 19 2/3 innings. He was sixth in the organization in strikeouts in 2011, with 117. He's an imposing figure at 6-foot-7, but staying healthy is imperative for the young hurler.
From the 2011 Draft
Jackie Bradley, OF: Bradley fell to the Sox last year, going No. 40 overall after a subpar junior season at South Carolina. Still, he's a rare center fielder rated as a plus defender with good speed. With Class A Salem this year, Bradley is hitting .384 with 25 doubles, 31 RBIs and 13 stolen bases in 53 games. Baseball America selected him as the best defensive outfielder in the Red Sox's system after last season.
Austin Laymance is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.