It has been no secret that the back line of Manchester United has been aging out in the last few years.
The retirement of Gary Neville signaled the ending of the guard, and departures of long serving members Wes Brown and John O'Shea to Sunderland over the summer continued that trend.
Rio Ferdinand has been a walking injured liability for the last few seasons as his appearances are gradually decreasing as time and age take a toll on his frame.
Nemanja Vidic likewise has started to succumb to multiple injuries and has hardly been seen in Red this season. Soon to be age 31, leftback Patrice Evra is also on his way out in due time.
There is hope in the youth that the club have, but time will need to see how the next wave of Phil Jones, Chris Smalling, Jonathan Evans and the Da Silva twins, Rafael and Fabio, will fare.
Even then there is room for additional players as the amount of games that the club play warrants having two quality options for each position in the long run.
Manchester United have started to rebuild their strong defense in the right way including much criticized goalie David De Gea, who is just as much a part of the defense as his four guardians.
Now it is up to Sir Alex to bring in the final pieces of the puzzle that will see United return their defense to the fortress that it has proven to be in the past.