When Niuman Romero , a 25-year-old infielder, went 0-for-4 against the Tampa Bay Rays earlier this month upon being called up from Boston’s Triple-A team the Pawtucket Red Sox, I was surprised. He had come out of nowhere, having been claimed from the Cleveland Indians prior to this season, and taking this into account, he fit the bill of someone who would have an immediate impact.

After all, other relatively unknown players thrust into meaningful roles have made sound contributions during the season’s first half.

He did manage to score a run in his only other appearance before being sent back down. It was bound to happen. The trend that was started by Darnell McDonald and Daniel Nava continued, albeit briefly.

Ryan Shealy, who has played with the Colorado Rockies and Kansas City Royals but hasn’t seen major-league action since 2008, was called up from Pawtucket to take his place. Maybe he will pick up where Romero left off.

McDonald, 31, began his career as a 19-year-old in 1998 and after six years in the Baltimore Orioles organization, played in the Tampa Bay Rays, Cleveland Indians, Minnesota Twins, and Cincinnati Reds systems before joining the Red Sox at the beginning of this season.

He was called up from Pawtucket when the injury bug severely decimated Boston’s outfield. Mike Cameron went down early on, as did Jacoby Ellsbury, who is still out.

McDonald saw limited action in his first 11 games, but he had seven hits in his first 17 at-bats. Both Ellsbury and Cameron were deemed ready to return from injury at the end of May, but Ellsbury’s condition worsened, meaning McDonald, who had just been released, had to be retained.

Boston has missed Ellsbury considerably, especially what he brings to the running game, but McDonald has played extremely well in his stead since being retained. He has appeared in 69 games now, and has a .272 batting average, six homers, 24 RBI, 22 runs scored, and six steals.

And today, he added to those respectable statistics, clubbing a two-run homer off Toronto Blue Jays starter Jessie Litsch in victory .

While his production has been ample, Nava has also proved very valuable. The former Independent-Leaguer started the season with Single-A Lancaster, made the trip to Double-A after an impressive .339 batting average, then hit .364 in 32 games with the Portland Sea Dogs before getting the call from the big club.

In early June, Boston placed pitcher Diasuke Matsuzaka on the disabled list, optioned outfielder Josh Reddick to Pawtucket, and put Nava in as the starting left-fielder.

All he did was hit a grand slam in his first at bat in a rout of the Philadelphia Phillies on June 12. He fueled off that to bat .291 in the month, and has remained consistent, hitting .364 with a .440 on-base percentage this July to bat a very efficient .300 overall. He has become a fan-favorite, and, along with McDonald, appears destined to remain with Boston at least for the remainder of the season.

Other relatively unknown players have stepped up as well. First, it was Cameron and Ellsbury, now it’s star second baseman Dustin Pedroia who is scheduled to miss up to six weeks with a broken foot. No reason to fret: Bill Hall and Eric Patterson have filled in nicely.

Hall, who spent the first six-plus seasons of his career with the Milwaukee Brewers and hit 35 homers in 2006, struggled to get on base during the latter stages of his career with the team, so he was let loose and after a brief and unsuccessful stint with the Seattle Mariners was given a chance by the Red Sox.

He has played second base, third base, and all three outfield positions in Boston. He struggled mightily out of the gate, collecting only 11 hits in his first 76 at-bats. But he has turned the corner with a heightened role. He was only 11 for 59 in June, but he had 10 RBI, more than April and May combined, and managed to get on base at a .371 clip despite the poor batting average.

So far in July he has hit .300, and in the series-opening rout of the Blue Jays he had three hits, two of which were doubles, and drove in four runs. Patterson, who can also play the infield and outfield, was terrible the first three months of the season with the Oakland Athletics, sporting a batting average near the Mendoza Line. But, upon being acquired in light of Pedroia’s injury during the end of June, he has performed admirably.

Manager Terry Francona has given either the unheard-of or historically woeful a chance to shine with Boston. He has made due with what he has at his disposal, which is surprising considering I didn’t think what he had could make due. Patterson has hit .271 this month, raising his batting average for the season to .217. He had three hits and two home-runs in a loss to the Tampa Bay Rays on July fifth as part of his resurgence.

Boston wants Ellsbury, Cameron, and Pedroia healthy. They need them if they want to make the playoffs and play deep into October. But for now, their replacements—castoffs and journeymen—are keeping the Red Sox within striking distance of the division-leading New York Yankees.

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