Scouting minors for the next Darnell

Even if they had not heard of him a week ago, most of Red Sox Nation knows well who Darnell McDonald is by now.

The Sox called up the 31-year-old McDonald to fill one of the two open spots in the outfield after Jacoby Ellsbury and Mike Cameron were sent to the disabled list on April 20, and he proceeded to hit a tying home run and a winning double in his first game. He followed that up with a game-saving assist from the outfield and a second home run the following night. Since his promotion, he has hit .333 with a 1.074 OPS, and has received the lion’s share of the playing time in center field, starting six of the first nine games after his promotion and coming off the bench in the other three.

McDonald's emergence as a viable major league injury replacement raises the question of who else is standing by in the Sox minor league system in case any of Boston's other starters goes down. Unfortunately, the answer is that there are not a lot of highly-regarded prospects in Triple-A, as many of Boston's highly-touted prospects are playing for Portland right now. However, there are a number of understudies with major league experience waiting for the call from Pawtucket.

Catcher: Who would get the call if Victor Martinez or Jason Varitek had to go on the disabled list?

The two minor league catchers currently on Boston's 40-man roster are Mark Wagner and Dusty Brown. Normally, Wagner, a ninth-round pick from the 2005 draft, would get the first shot with the big league club if a need arises. He is above-average defensively with a very strong arm, throwing out 42 percent of would-be base stealers over his minor league career. By comparison, Victor Martinez and Jason Varitek have combined to throw out just 8 percent of baserunners in 2010, last in the American League.

But Wagner is out for six to eight weeks with a broken hamate bone in his left hand that will require surgery Tuesday. Even before the injury, Wagner had been inconsistent offensively, hitting .267 over his minor league career while showing extended flashes of excellence, such as hitting .301 with Portland over the first half of the 2009 season. The 25-year-old was hitting .222 over his first 16 games with the PawSox in 2010.

Brown is an organizational mainstay, having been with the Red Sox organization for nearly nine years. He made his major league debut last June and saw action in six games with Boston in 2009. The 27-year-old has thrown out baserunners at a 26 percent clip over his minor league career and sports a .262 career batting average. He is presently hitting .256 in Triple-A, where he was platooning with Wagner. The catchers had split time almost evenly behind the plate for Pawtucket in 2010, with Wagner starting 12 games at backstop and Brown starting 10. Obviously that's all about to change.

First base: Who is the insurance for Kevin Youkilis?

While Mike Lowell and Victor Martinez would likely see most of the playing time at first base if Youkilis were to land on the disabled list, Boston would probably call up Aaron Bates if they needed another option. Bates, 26, demonstrated plus defensive skills during a brief major league stint in July 2009 while also hitting .364 in five games with the Red Sox.

Offensively, Bates has always shown a lot of power potential, but has struggled with making consistent contact and elevating the ball since reaching Double-A in 2007. He has had a few extended hot streaks at the plate during that time, highlighted by a stint in which he hit .340 for the Sea Dogs for the first two months of 2009. He is presently hitting .250 in Pawtucket with two home runs and a .760 OPS. Ultimately, if a temporary hole opens up at first, the front office will not hesitate to call up Bates for his defensive capabilities; they’ll just have to hope to catch him when he is peaking offensively.

Lars Anderson could get a look later in the season. Universally regarded as the top prospect in the system heading into 2009, Anderson struggled over the course of the season, partially because of injuries and partially because he simply wasn't able to hit his stride. However, he is back to form early in 2010, hitting .355 with five home runs for Portland, earning a promotion to Pawtucket on Thursday. Although the Sox front office was not shy in promoting Anderson to Triple-A at this early stage of the season, they may take their time with the 22-year-old to allow him to continue to build his confidence back up before promoting him to the majors.

Infield: What happens if Dustin Pedroia, Marco Scutaro or Adrian Beltre get hurt?

Here's where the team may run into some problems. Up until this week, Pawtucket’s starters at second, third and shortstop have generally been Tug Hulett, Jorge Jimenez and Kevin Frandsen respectively -- none of whom are know for their defensive abilities. While all three hit well in spring training, none have been especially impressive at the plate for the PawSox, with Hulett hitting .175, Jimenez .194 and Frandsen .258. Additionally, Frandsen was designated for assignment earlier in the week, and was claimed off waivers by the Angels on Thursday.

Absent immediately-viable options from that pool of players, Boston may give versatile infielder Angel Sanchez an opportunity. The 26-year-old was signed as a minor league free agent this offseason, and can play shortstop, second and third adequately. He failed to impress the Sox brass with his bat in spring training, but he is hitting .328 for the PawSox, while splitting time at all three positions and at designated hitter. The front office would need to open up a spot on the 40-man for Sanchez, which would not be difficult if they opt for him over Hulett, who could be designated for assignment.

Two names that may be major league depth options later in the season -- but who are not likely immediate options -- are infielder Gil Velazquez and shortstop Jose Iglesias. Velazquez is no stranger to the I-95 shuttle between Boston and Pawtucket, but he is on the disabled list with a fractured right thumb and is probably another couple of weeks from returning to the field. As for Iglesias, the Sox will likely let him build up his comfort level in Portland and exhaust all other reasonable options before thrusting him into major league action at the age of 20. That being said, don’t be surprised if he gets a cup of coffee in September.

Outfield: What if there is another opening in the outfield?

Boston’s major league outfield is obviously in flux right now. With Ellsbury and Cameron on the disabled list, the team has been forced to go with a starting outfield of J.D. Drew, Jeremy Hermida and McDonald, while using Jonathan Van Every and Bill Hall as fourth and fifth outfielders.

If the need arises for another outfielder prior to Ellsbury’s or Cameron’s return, Josh Reddick will almost definitely get the call, being the only other outfielder on the 40-man roster and the only other outfielder in the system with major league experience. While the Sox would prefer that Reddick play every day while he is still getting used to facing advanced pitching, another injury would almost certainly force the team’s hand.

After Reddick, the next two outfielders in line would likely be Daniel Nava and Ryan Kalish. Again, both are better-served developmentally by playing every day rather than sitting on a major league bench, but there is also a lot to be learned from spending that first week in a major league clubhouse.

Nava, 27, is a small-framed switch-hitter who plays corner outfield. He does not possess much power, but he has an outstanding approach and has led the organization in batting from 2008-2010. He hit .341 for High-A Lancaster in 2008, combined to hit .352 for High-A Salem and Double-A Portland in 2009, and is presently hitting .309 for Pawtucket. After proving himself at every level up the ladder, it may soon be time for Nava to get a major league opportunity.

Kalish, one of the top prospects in the Sox system, has played all three outfield positions for Portland this season. A ninth-round draft pick in 2006, Kalish has shown excellent all-around tools, including the ability to hit for average, outstanding plate discipline, improving power, above-average speed, an average arm and a solid glove. Still just 22, he is a viable option as a potential major league starter down the road. If he can show a little more consistency at the plate and continue to increase his power numbers, Kalish should earn himself an early promotion to Pawtucket. At that point, he could get called up to the bigs at any time, and he very well may be the next player to make a Darnell McDonald-type splash in the majors.

Andrews is designer and developer of SoxProspects.com and a special contributor to ESPNBoston.com.