After the season-ending injuries to captain linebacker Jerod Mayo and captain nose tackle Vince Wilfork, the Patriots were left without any named leaders on defense. That's not to say players aren't leaders on that side of the ball, but there were no official defensive captains remaining on the active roster.
That void has now been filled by fourth year safety and former two-time captain Devin McCourty.
McCourty returns to the position after having not been named a captain for the 2013 season, after earning the title in 2011 and 2012. While he won't be calling the plays on defense (that will fall to sophomore linebacker Dont'a Hightower), McCourty will be expected to fill the void on a surprisingly young unit.
Other leaders, like Rob Ninkovich, could earn the second captaincy position on defense, but that will be entirely up to Belichick to decide.
Without Wilfork and Mayo, the old men on the defense are 30 year old safety Steve Gregory and 29 year old DE Ninkovich. The other starters on the 4-2-5 defense are 6 year veteran CBs Aqib Talib and Kyle Arrington, 4 year veterans McCourty and LB Brandon Spikes, sophomores Hightower, DE Chandler Jones, and CB Alfonzo Dennard, and rookie DTs Joe Vellano and Chris Jones.