Manchester United boss David Moyes will be particularly worried by his side's inability to defend this season with the Premier League champions conceding nine goals in seven Premier League games thus far.
The centre-back partnership of Nemanja Vidic and Rio Ferdinand seems to be failing to live up to the heights of years gone by with both players suffering with injuries and poor form during the course of the season.
Vidic was at fault for Sunderland's first goal at the weekend as the Serbian defender cleared the ball to Craig Gardner to put the Black Cats one-nil up.
Ferdinand on the other hand has not featured since United's 2-1 defeat against West Brom on September 28 due to what Moyes described as a 'slight groin injury'.
With Vidic out of form and Ferdinand currently struggling for fitness, maybe it's time for Moyes to give Chris Smalling and Phil Jones a long run of matches.
The two England internationals have been used sparingly throughout their Manchester United careers - due to the outstanding form of Ferdinand and Vidic over the last few years.
Whenever the duo have shone in the absence of either Ferdinand or Vidic, they are often quickly dispatched back to the substitutes' bench despite their previous performance.
The Manchester United duo - at 23 and 21 respectively - have the fitness, pace and ability to be handed the responsibility of playing in the heart of the Red Devils' defence.
Sir Alex Ferguson forked out a combined total of £24m on the duo so obviously believes they are good enough to represent a side of Manchester United's stature.
Moyes has a tough decision to make during the next fortnight as Vidic and Ferdinand's experience is second to none, but Smaliing and Jones are United's in-form centre-backs at the moment and they deserve a chance to shine.