Cardiff City centre-back Sean Morrison has been one victim of Steve Morison's appointment as the Bluebirds' manager so far.

Despite starting in the 38-year-old's first two games in charge, he has failed to play a single minute since then with the captain being benched in recent games against Huddersfield Town, Preston North End and most recently at home to Hull City last night.

Curtis Nelson, Aden Flint and Mark McGuinness are the centre-back trio that have been preferred in those three matches, leaving the ex-Reading man in an unusual situation having previously been an ever-present figure in the Welsh side's backline since his arrival in 2014.

At 30, arguably approaching the end of his peak as a professional footballer and with his contract at the Cardiff City Stadium expiring in the summer, there would be a case to cash in on him whilst they can if a bidder came in.

However, there is an even bigger case to retain him for numerous reasons.

Firstly, the 30-year-old is still club captain and according to new manager Morison, he has been the ultimate professional about his current situation despite temporarily being left out in the cold as one of the first people he calls if he requires anything.

Understandably, he's not happy about his lack of first-team opportunities but has managed to balance that with remaining composed, the perfect combination of personality traits needed to be an effective captain.

He may not be getting chances on the pitch, but it certainly seems as though the centre-back has been a huge character behind the scenes and that has been reflected in recent performances before their setback against Hull City last night.

With an inexperienced manager at the helm, having someone like Morrison at their disposal can only be a benefit and you could imagine him playing a similar role Matt Grimes currently is at rivals Swansea City with another young boss in Russell Martin.

That's why it was so important for the Swans to tie the midfielder down to a new contract - and is why the Bluebirds should be retaining their own skipper beyond the January window.

The second main reason why he should remain at the club is to help in embedding his new boss' philosophy.

Not only is he a vocal leader on the pitch and with that, can be crucial in getting his teammates into the right positions, but he also provides the depth required for the second-tier outfit to operate with three at the back.

This system may change to a flat back four at some point, but a 3-4-2-1 formation seems to suit the players they currently have at their disposal, with Morrison, McGuinness, Nelson, Flint and Ciaron Brown providing more than enough options at centre-back  to be utilised when all are fit. Losing the former now would leave them light on options.

With this ability to play a back three, this gives Perry Ng and Ryan Giles the license to get forward, something the latter especially thrives off and could give a reasonably inexperienced Joel Bagan less defensive responsibilities to attend to if he succeeds the Wolverhampton Wanderers loanee as the club's first-choice left wing-back at some point.

Not only would a back three give the wing-backs less defensive chores, but also some of the younger players in a more advanced role including Rubin Colwill and Isaak Davies who can express themselves without the fear of needing to drop back too deep when they lose possession.

These knock-on effects of keeping Morrison just shows how much of a key cog he is in his side's machine despite being left out at the moment - and all it takes is one injury or suspension for him to return to the heart of defence.

Keeping him is a non-negotiable - and giving him a one-year contract extension wouldn't be the worst idea either if they can afford it.