The Severnside derby kicks off the return of the Championship.
Like most local derbies it draws a decent amount of attention and this one has the added Wales vs England element too.
However this one is likely to attract a bit more scrutiny given the events at Cardiff during the international break.
Paul Trollope lasted 11 games in charge and in some respects its surprising he lasted that long.
I'm not usually one for sacking a manager early but in Trollope's case I'm not convinced it was going to work out.
He'd already switched from his initial 5-3-2 formation and tactics, and credit to him for that, but according to the data things were getting worse, not better.
It’s a shame it ended this way as statistically speaking, the season appeared to have started fairly well.
For the first six weeks Cardiff had a decent overall shots on target share above 50% at 11v11 and at level score situations.
However, the Bluebirds' all shot share (Corsi/TSR) only once made it above 50% either under all conditions or at level score situations.
But (poor) shot quality matters.
And when we look deeper into the data we can see why the results did not reflect this limited early season promise.
Trollope's attack, whether by design or simply through not having any other options, had been focused on headed and long range attempts at goal.
While a varied attack can prove profitable (see Brighton), Cardiff have exchanged a sizeable amount of shots from prime positions into headed attempts.
This is not a good exchange to make.
By week 11, Cardiff had taken the third fewest footed attempts at goal in the danger zone (six-yard box and centre of the 18-yard box) in the division - only Rotherham and Ipswich have taken fewer.
Despite being middle of the pack defensively, Cardiff have the joint fifth worst danger zone shot difference - again Ipswich and Rotherham are two of the teams below them.
Looking at the headed attempts at goal, the situation is give-or-take a near perfect mirror image.
Cardiff have the directed the third most headers at goal (behind only Barnsley and Aston Villa), and have conceded the third fewest.
While it may delight commentators to regularly swing the ball into the box, such a one-sided attack does not usually prove effective as headers are much less likely to be scored than attempts from the feet.
Sadly, Cardiff have the second lowest % of their shot attempts being taken from the centre of the 18-yard box (Ipswich lowest).
In fact, Cardiff have been making almost two thirds (63%) of their attempts on goal as headers outside the six-yard box or shots from outside the 18-yard box.
It is entirely possible that taking so many attempts from poor locations is playing a part in the awful shooting % figure.
By contrast, Cardiff have forced just 56% of attempts at goal from these poorer locations.
So instead we have Neil Warnock joining the show.
Personality-wise, Warnock has had something of a love-hate relationship with Cardiff fans. He’s generally been complimentary about the club and its fans, but during his travels around the league he’s managed to rub a lot of Bluebirds up the wrong way.
Still, this isn’t a popularity contest – this is, of course, a results driven business and following guiding Rotherham to safety last year and his wealth of previous experience, Warnock would seem to be an obvious choice.
But how much of last year’s great escape was down to Warnock’s influence and is he likely to have a similar effect on Cardiff?
Well, having gone through the data I’m not convinced Warnock had that big an effect on Rotherham’s survival.
He took over from Neil Redfearn after 30 games with Rotherham battling Bolton, MK Dons and Charlton to avoid relegation.
Credit where it's due?
In the end the Millers completed the task relatively easily (nine points above safety), but I suspect that may be as much down to the awfulness of the other three teams as to Warnock’s magic.
As you can see in the chart below, at level score Rotherham’s all shot share (Corsi/TSR) and unblocked shots share (Fenwick) remained pretty unchanged from Warnock’s start to the end of the season.
There was a slight uptick in shots on target share (green line) but this still never broke the 45% mark – hardly earth shattering but useful at the bottom of the table.
The biggest changes, however, came in the rate Rotherham scored their goals and kept them out.
The Millers’ combined shooting % and save % (PDO) was its lowest of the season (just) when Warnock took over – 17 points below league average.
By the end of the season Rotherham’s PDO had made up 15 points of this difference – with the save % being the main benefactor by more than 10 points.
And it’s so much easier to win games sneaking the odd goal when you’re not shipping them constantly.
Combined with a smaller but important increase of five points in shooting % and Rotherham were just a shade under league average in these key metrics by the end of the season.
So could Warnock have instilled a tactical change to improve these measures?
Well, in all his changes gave Rotherham one extra shot from the centre of the 18-yard box per 7.5 games… so two more shots from this area during his spell in charge than Redfearn would have expected.
But there were ten extra headers inside the six-yard box compared to Redfearn and shots taken from outside the 18-yard box were cut down significantly.
So it is possible this could have accounted for the increase in shooting %.
How about defensively?
Well, aside from a very small drop in the number of headers allowed inside the six-yard box, this does not make great reading.
Warnock’s team conceded more shots per game from the centre of the 18-yard box (+0.5), the sides of the box (+0.24) and outside (+0.9) than Redfearn’s side averaged.
The increase in shots outside the box would be far less of a concern if it meant shots inside the box were being pushed out, but this did not happen.
Of course, the situations may have been different – perhaps Warnock’s defensive system meant opposition players were closed down more frequently when taking shots resulting in poor quality chances.
However, there’s little evidence in my data to suggest anything other than a more normal save % and shooting % driven recovery.
Indeed, at level score under Warnock 35% of shots on target taken were hitting the back of the net and more than 86% of shots on target conceded were saved – both way above league averages of 30%-70%.
For Cardiff fans, it seems that it might be a case of more of the same as regards the aerial based attack, although there may be a focus to not shoot from distance so much.
Also, it is probably fair to say that Cardiff's squad is more talented than Rotherham's (especially given the free agent signings made in the last week) so one would hope Warnock can get more out of this talent.
But perhaps its most notable that in this young season Cardiff have the second lowest shooting % and save %, to give a PDO of just 78.44 – lowest in the entire division by some way.
It’s safe to say the team is due something of a rebound, how much we will have to wait and see.
