Good football teams are so often defined by the quality of their spine. Match-saving goalkeepers, leaders at centre-half, engine room central midfielders, and goal-getting strikers. It might be a simplistic way to put it, but without quality all along their backbone, teams will really struggle to find consistency.

Going into the summer, we knew that last season’s promotion-winning squad needed some reinforcements.

At centre back, the departures of club captain Michael Morrison and young star Mamadou Jobe forced our hand. Up front, a new focal point was needed. But in central midfield, the challenge was slightly different – it was more a case of adding some quality rather than quantity to help upgrade the department for the bigger challenges a new division would throw at us.

Of the five options available to us at the time of writing, four of them were with the U’s last year: Dom Ball, Shane McLoughlin, Pelly Ruddock Mpanzu and George Hoddle, with just Korey Smith departing and being replaced by the arrival of Owen Moxon. All five have characteristics to be excited about, and it feels like a strong unit for Neil Harris to pick from.

But with the recent drop-off, are we seeing a problem with the possible combinations? We’ve struggled for control in games, and each match has presented periods where we’ve felt unable to get a grip on proceedings. Might that be because Harris is struggling to find his preferred partnership in central midfield?

The first thing to say is Ball is probably one of the first names on the team sheet. A club captain, experienced leader, and one of the most consistent performers of the season so far. We’ve felt his injury absence acutely over the past few weeks. So the question becomes, with everyone fit, who is the best pairing for him?

Shane McLoughlin is the first one to look at. He is an intriguing case; released in May and then re-signed in July alongside Shayne Lavery, while it didn’t feel inspiring at the time, his performances have been at a high level. It’s no coincidence that the 1-1 draw at Sheffield Wednesday was the one where McLoughlin was able to start, playing impressively on his return from another injury.

This spell of games has solidified the idea that whatever the combination, one of McLoughlin or Ball must be in there. They offer a control, physicality, and mobility that any combination of the other three just doesn’t. If both are fit, it would be an interesting combination to look at more regularly. But with McLoughlin, fitness is unfortunately a big question mark.

If someone else has to partner either of them, Mpanzu is often the first choice. As each game goes by, however, he is proving that he should really be exclusively considered as a number 10, playing further forward nearer the striker. When he plays deeper, games seem to often pass him by. He’s better deployed as someone who has the license to try a Hollywood pass and help with an aggressive press further forward, rather than dictate tempo and control possession.

George Hoddle has so much promise. His cameo at Barnsley and role in the goal is everything you need to know about him. He loves finding half spaces around the box, playing delicate passes.

Moxon is similar – he doesn’t want to be dropping deep to take the ball from the centre-backs and help dictate play. He’s a box-to-box midfielder, but he should have a playmaking license around the box. His dead balls, crosses and strikes from distance are his strong suit, so when he and Hoddle play together it feels like they’re trying to do similar things going forward.

The Leyton Orient and Bristol Rovers away games show that any combination of those three just doesn’t seem to work. Five goals conceded, and zero scored back that up. None are defensive-minded enough to provide any protection for the backline, and don’t provide the right balance going forward.

Especially with Ball still injured, it’s the latest problem Harris has to find a way to solve. Last season, we saw him tackle each problem as the season went on, from consistency to away form to formations. This isn’t so much a recruitment problem as a tactical one. The pieces of the puzzle are there, he just needs to find the right combination.