The mid term reports focus now on the midfield and wingers. I covered Brown in Brown: A Never Ending Story as he has a unique role in the side. Let’s now consider the rest of the midfield.
PS I will include Brown in this for completeness.
Celtic’s midfield and wide attack has largely been about Brown, McGregor, Christie and Forrest. A Scottish quartet remarkably. Morgan, Johnston and Elyounoussi have all contributed about a 3rd of those lot and Ntcham half. Sinclair doesn’t have enough minutes to count (sad face).
Defensive Performance
Let’s start at the back and work our way forward. It’s generally a nine-man defending game these days so defensive actions count. Position will be more relevant here but these are the key metrics:

What I would draw your attention to from this is:
Brown and his unique (regressing) role
McGregor is defensively stronger this season
Hayes’s numbers reflect his left back stints more than anything
Christie’s numbers are impressive for a number 10 or advanced winger
Forrest has strangely regressed defensively
Ntcham’s numbers reflect his stints at 10 (but see Christie for what is possible)
Ball Progression
The following compares Pack Passing (ability to get the ball forward through opponents) with Dribble Progressions (Pack Dribbles plus Progressive Runs).

Whilst no one is in the Weak / Weak category (Elyounoussi at a stretch), the other main conclusions to draw are:
Hayes looks really good by this view – strong in passing out from left back (if not pass completion overall) and good at ball progressions by dribbling
No surprises that Johnston and Morgan are effective with ball at feet
Christie is bang in the middle – not faint praise – he just does everything pretty well
McGregor has overtaken Ntcham as the Pack Pass king – this is a reflection of McGregor’s deeper role and Ntcham’s more forward position
But McGregor should be strong in both categories
As I showed yesterday Brown is executing more Pack Passes
Forrest - despite the goals, not much going on here again – strange
Chance Involvement
The next chart plots Open Play Chances Created per 90m (Assists + Key Passes) with Secondary Assists 90 (passes to the person who set up the shot). If I include chances created from corners and free kicks, Christie would be in his own little island near the top left. So, let’s consider a level playing field and only include Open Plan chances.

The conclusions?
Given his limited playing time, Rogic is not a long way from Christie, which surprised me.
I feel like I am always having to justify Ntcham. Are you starting to get why he has to play?
Forrest (finally!) is strong on chance creation and this is reflected in his burgeoning assist total
Johnston is a little disappointing as is the direct Elyounoussi
Morgan – well you can see for all the endeavour, there is limited output
Assists / xA
Filtering out Key Passes and concentrating on Assists versus Expected Assists (xA), gives us this picture:

The lowdown.
I’m worried by this. All the major creative talents are overperforming their xA – i.e. getting more assists than the chance quality would suggest. It is a problem as it is unlikely to be sustainable.
In particular Johnston has the highest Assist90 rate yet his xA is nowhere near that expected. Elyounoussi likewise.
Forrest is leading the charts with 16 assists but he is also overperforming his xA by quite a bit.
The one with the most realistic contribution is strangely Rogic. He only has 3 assists though.
McGregor has dropped off alarmingly – Celtic are just not getting him into threatening enough positions.
Goals and xG
And we now compare Goals with Expected Goals (xG) in a similar manner:

Sadly, a similar picture. All major contributors are exceeding expectations which is difficult to maintain.
Forrest, exceptionally, is round and about his xG contribution.
Johnston once again is massively over achieving. He is either due a sobering bump to the mean, or he is Messi incarnate. What are the odds?
To hammer home the point, here are xG and xA combined into Scoring Contribution and xSC (Expected Scoring Contribution):

Normally some players are ahead of expected and some behind. Having all your major contributors ahead of expected would worry me that so far they have got better outcomes that they could expect and unless chance quality improves that will drop off.
If you look back at 18/19 then Forrest and Christie (now on penalties) are the only ones that have really improved their xSC over last season.
The overriding message here is of potentially unsustainable overperformance and lack of squad improvement in attacking output from midfield.
Conclusion
Celtic have seen many changes in the midfield configuration this season. The net result of that has been that McGregor has been neutered whilst Christie has flourished as a 10. Ntcham remains vital to the side for his deep creative abilities.
But I am concerned that despite the eye-catching numbers like Christie 17 goals and 15 assists and Forrest 14 goals and 16 assists. And despite Johnston and Elyounoussi having amazing per 90m averages, the whole thing does not look sustainable. Not all the midfield can overperform their xA and xG over the whole of a season you would think.
Celtic need to carefully consider their midfield configuration to ensure Ntcham is creating a bit deeper, McGregor is allowed to contribute more in an attacking sense, and that there is some consistency to attacking shape.