THIS week, Oxford United reminded us they will not always be able to dig themselves out of a hole.

The U’s have masked their defensive vulnerability by outscoring the opposition or grabbing late goals so many times this season, but they did neither against Plymouth Argyle and Morecambe.

When you are not keeping clean sheets, that will only lead to one result.

Elliott Moore’s return will be a huge boost, even though none of the centre backs who started the last two games have been poor.

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But with all his defenders fit again, Karl Robinson can hopefully name a settled back line for the rest of the season – and that could be vital.

The U’s have used 18 different defensive combinations in 41 Sky Bet League One matches due to injury, illness, suspension, loss of form, arrivals and exits.

Many of those factors are out of Robinson's control, but it is no coincidence that United are 17th in the clean sheets 'table' with eight all season.

That is the same number as 23rd-placed Doncaster Rovers and three fewer than Gillingham, who are 21st and shipped seven goals against the U's in January.

Robinson has said that you cannot expect United to score so many without a trade-off at the other end of the pitch.

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That is absolutely a fair point, but it is now in the head coach's power to name a settled defence and the statistics suggest this will have an effect.

So far this season, five of United's eight clean sheets came on the 15 occasions they did not rotate their back line, compared to three in the 25 games they changed it up.

The U’s still have to play three promotion contenders in Sunderland, MK Dons and Rotherham United.

As we saw at Plymouth, those matches could well be decided by the odd goal.

Defensive resilience will be key and some stability will do the U’s no harm in their search for a first clean sheet since February.