THE question of whether or not Scott Brown should be starting every game for Celtic seems to rear its head on an annual basis. There are those who are quick to write him off every year (and I include myself in that), and then there are others who point out that the talismanic captain has a happy habit of making the naysayers look very foolish indeed as his performances pick up.

It is quite the quandary. No one is doubting Brown’s importance to the Parkhead club over the last decade or so, but even his more ardent admirers will admit that he is not the player he once was. The dynamism that typified the combative midfielder’s style of play for the best part of his career has eroded over time as Brown finds himself playing a more cautious role in the starting XI; recycling play and taking fewer risks, all the while barking out instructions to his team-mates.

Brown’s succession is coming, though, and Neil Lennon will have to manage the situation delicately when it does. And when we dig into the numbers behind Brown’s recent performances, we can see that day might arrive sooner than the Celtic boss anticipated.

There is no question that Brown was one of the Premiership’s best defensive midfielders last season. Across a whole bunch of metrics, the 35-year-old stands out among his contemporaries, leading the way in some categories. But this season, in the handful of games that we have to go on, we are seeing a marked decline. As an aside, it should be pointed out that all the data referenced is from Premiership fixtures.

The number of defensive duels Brown attempts per game has fallen this season, as has his success rate (from 62.5% to 50%). The Celtic skipper is contesting marginally fewer loose balls per game (although, it must be said, winning incrementally more of them) while the number of successful interceptions completed per game has fallen by 50%.

His passing statistics have remained largely the same so far this season, but it is Brown’s defensive output that is worthy of scrutiny. It’s these abilities out of possession that have made Brown so important over the years and now that these are on the wane, the question must be: what is he actually contributing to the team?

Certainly, from a creative perspective at least, close to zero. Expected Assists (xA) work in largely the same way Expected Goals (xG) do; the probability of a chance being converted is calculated, and this figure tells us both the frequency and the quality of the opportunity. Currently, Brown has an xA/90 minutes of 0.025 – equivalent to one assist every 40 games. Last season’s figure was almost identical.

That might be brushed off by some as a load of number-crunching nonsense but Brown’s xA is highly demonstrative. You have to go back to Celtic’s 3-1 win over Rennes in the Europa League in November to find the last occasion Brown laid on a goal for a team-mate, and all the way back to February 2019 for his last domestic assist. In the last two seasons, these are the only occasions where Brown has teed up a goal for his side.

There has been a serious lack of creativity in Celtic’s midfield so far this season – both their goals scored and xG per 90 have decreased compared to the previous campaign – and there is no question that Brown is the biggest culprit. Only one in four passes that Brown has made this season go forward; the rest are either lateral or played behind him. Proportionally, he averages fewer passes forward, into the final third and into the box than any other midfielder on the books at Celtic Park.

If it is creativity that is required, then Lennon could do a lot worse than giving his new recruit David Turnbull a run in the team. Despite playing for a Motherwell side that hasn’t really got going yet this campaign, the 21-year-old has the highest xA/90 of any player in the Premiership. What this means is that in essence, Turnbull fashions excellent opportunities but was let down by his former team-mates’ profligacy.

The Fir Park youth product has a lower passing accuracy than the likes of Brown but the fact that he is willing to play risky passes in an attempt to open up the opposition makes him more valuable in this regard. It’s the same story with Olivier Ntcham – a far greater proportion of his passes are forward ones and by their very nature have more risk attached, and his overall accuracy suffers as a result. But it is the type of passes, and not their overall accuracy, which is important here.

Callum McGregor, Ntcham and Turnbull all try to split their opponents’ defence open. Sometimes these passes fail but when they come off, they leave the other team vulnerable and goals often follow. But when you’re a team like Celtic, who dominate possession in every domestic game and near enough every fixture is an exercise in breaking down your opponents, isn’t it more valuable to have someone in the side who will break the deadlock, rather than simply moving the ball from side to side? After all, keeping a hold of the ball isn’t the problem. At the moment, Celtic’s problem is that they are not using it correctly.

The stats point to an obvious conclusion: the days where Brown’s place in the starting line-up week in, week out are coming to a close. But football is not played on a spreadsheet, and it would be remiss not to mention the more ethereal and impossible to measure qualities Brown has.

The Celtic captain is a leader in every sense of the word, and that surely translates in some way to he and his team-mates’ performances on the park. His constant cajoling and motivating, the way he issues instructions – these are important aspects of Brown’s longevity at the heart of the Celtic midfield.

The question that Lennon will ultimately have to answer is philosophical in nature. At the end of the day, what is more important: the tangible, real-world benefits the statistics suggest will arrive with the introduction of a creative midfielder in Brown’s stead, or the abstract qualities that have made him a Celtic legend?

The pragmatic approach is surely the former. There are precious few industries where intangible benefits are preferred to material ones, and with good reason. To borrow that old cliche, football is a results business and the data implies that Brown is harming his side's chances of winning matches. His time at Celtic is not up but his regular starting berth, come rain or shine, should be. There are others who simply offer more and while it may be unpalatable to some supporters or the club's coaching staff, the moment has arrived for Brown to be phased out.