How deep are the 2011 Boston Red Sox? Deep enough that the biggest roster question surrounding the team is who will serve as the sixth starter.

That’s an exaggeration, but only a slight one.

The team has some tough decisions ahead of it, such as answering questions concerning the batting order, and who makes the bullpen.

But the team is solid enough that one of its major concerns is trying to figure out who would jump into the rotation should a starter go down with injury.

It’s a concern based on recent history.

Josh Beckett, John Lackey, Clay Buchholz and Daisuke Matsuzaka have all spent time on the disabled list in the past two seasons.

Tim Wakefield is the obvious choice to join the rotation if someone can’t make a start.

He’s thrown more than 2,800 innings for the Sox in the past 16 seasons and is third on the team’s all-time win list.

Yet he is coming off his worst season with the team and must commit himself to being a reliever when the staff is fully healthy.

There are other, younger alternatives for the Sox to keep around as rotational insurance.

Alfredo Aceves has been a find, a former Yankee who went 14-1 with a 3.21 ERA in his time with New York.

He has an impressive strikeout-to-walk ratio (87-to-30), and he gave up just one run on three hits in three innings against his former team last week.

There is also left-hander Felix Doubront, who made the most of his chance to shine in the injury-plagued summer of 2010.

Doubront, 23, went 2-2 with a 4.32 ERA for the Sox last season. He is expected to someday be a middle-of-the-rotation starter for the team.

Doubront is coming off an elbow scare and just began throwing off a mound again last week.

He admits that the thought of needing Tommy John surgery crossed his mind, but both he and the team are now proceeding under the assumption that three weeks of rest was enough to take care of the problem.

Both Aceves and Doubront are considerably younger than the 44-year-old Wakefield.

Speculation about the end of the knuckleballer’s career ran rampant last week after Terry Francona refused to endorse any one of the three as a favorite for a roster spot.

Some writers made it clear that they think a roster spot is a precious thing to use on a pitcher whose main responsibility is waiting for a spot start.

Yet Wakefield proved late last season that he can be effective out of the bullpen.

From August on, he appeared as a reliever in eight games, throwing 141/3 innings and giving up just two earned runs.

He also made three starts in that span, showing his flexibility once again.

Giving Wakefield one of the six or seven bullpen spots at the start of the season makes sense.

Both Aceves and Doubront have options remaining, so there would be no penalty for sending either pitcher down.

In Pawtucket, both pitchers could remain stretched out as starters, ready to provide even greater starting depth should the big club need more help.

And Wakefield can be the team’s long reliever, waiting to come into a game or get back into the rotation if the need were to arise.

It isn’t the role a pitcher dreams of, but Wakefield has endured bigger setbacks along the route of his resilient career.

Tom Caron is the studio host for Red Sox broadcasts on the New England Sports Network. His column appears in the Press Herald on Tuesdays.