Some time has passed and the dust has now settled on Celtic's defeat away in Portugal at the hands of Benfica. The result means that the Hoops have started off their Europa League campaign with two defeats. That is far from ideal.

Celtic do not have much time to dwell on the result though, as the games keep coming thick and fast. Their next one is against Hearts at the weekend.

Celtic must keep winning in the league as the Rangers have found some form and are cranking up the pressure on Martin O'Neill's side.

So, the Hoops would like to have their best players available moving forward. But there is some concern about the fitness status of one key player going into the game against Hearts.

Is Celtic player carrying a knock?

When the lineup against Benfica came out, there was one clear surprise. Liam Scales had been left on the bench in favour of a starting centre-back duo of Dane Murray and Auston Trusty.

It was a curious decision, to say the least. Murray simply does not have the experience at this level and has often faced criticism from the fans for some of his performances this season.

It would be safe to say that it did not work as well as O'Neill would have hoped for. After all, Celtic did end up conceding four goals, and it could have been more.

As for Scales, could the Irishman have been carrying some sort of knock, which played a factor in O'Neill's decision-making against Benfica?

As reported by CeltsAreHere, Charlie Mulgrew said while speaking on Premier Sports Ireland: “Scales, you can only assume he’s got a knock and is being rested. Because I think you see how big a player he is for Celtic. It’s not always appreciated but he is somebody who heads the ball in the box and defends well.”

Celtic need players like Liam Scales right now

Celtic certainly appeared to miss Scales against Benfica. At times, it felt that they were too easy to open up for the hosts.

Despite that, O'Neill did not bring on Scales and kept him on the bench as an unused substitute.

Nothing has come out since then that would suggest that Scales is injured, which should raise a few more eyebrows about the decisions from O'Neill against Benfica.

It remains to be seen if Scales will be involved against Hearts at the weekend or not. To be honest, it does feel like Celtic could do with experience and leadership at the back at this point in time, as they try to get past a rough patch of form.

They have lost four of their last five games across all competitions. There is little room for error moving forward. If the results do not improve, they might have little choice but to part ways with O'Neill.