Tony Calvin: Taking on Cap Du Nord with Slave and Red in Saturday's Doncaster feature

The downside of a form-line working out is that the betting lemon is often squeezed dry as a result (naff line but you get the picture), and punters have to decide whether that is the case with Cap Du Nord in Saturday's Skybet Chase at Doncaster.

He was available as big as 16/1 in the marketplace earlier in the month and was 6/1 on Saturday morning, but he is now into 5/2 (from 3/1 on Monday) with the Betfair Sportsbook (and a touch bigger on the exchange at the time of publishing) after his Kempton conqueror Royale Pagaille put himself bang into the Gold Cup picture after his runaway win in the Peter Marsh at Haydock on Saturday.

So is Cap Du Nord's shortening in price justified?

Undoubtedly well handicapped but is the ground a concern?

The Kempton form-line could not be working out that much better, that much is true.

Cap Du Nord went into that handicap on the back on an impressive Newbury success off 123 (from subsequent Rowland Meyrick winner Canelo, who is the 5/1 second favourite in here), and he ran Royal Pagaille to 3¼ lengths off a 10lb higher mark at Kempton, albeit the winner absolutely gagged up.

The third, Double Shuffle, was beaten 22 lengths and came out and won next time, and even the seventh (beaten 54 lengths) advertised the form when beaten just ¾ length in the Somerset National last week.

So it is clearly a very lively piece of form, and one that suggests that Cap Du Nord could still be thrown-in - well, at the very least one who remains favourably handicapped - off just a 6lb higher mark. In fact, he needs to win this (or another race) to make sure he can take up his intended place in the Grand National in April.

I am not sure where the improvement has suddenly come from as an 8yo with 19 chase starts under his belt (both from him and Royale Pagaille, in fact), but it seems inarguable and I wouldn't be in a mad rush to lay him at around 3/1 on the exchange myself for the Donny contest, it has to be said.

However, if these big handicaps were this easy then us all slapheads would have had the surgery and be looking like Hair Bear from the Wonderland Zoo by now, and I imagine connections of the favourite will be a touch worried by the ground.

It is heavy with yet another very wet week in store, it seems (one site says they will get 17mm alone on Thursday, and another 10mm) and Cap Du Nord's record on that ground is 0 from 3.

In fact, he is also 0 from 7 on soft, albeit that Kempton run came on the latter and maybe the horse has simply come to himself now and he can handle anything these days.

But maybe a slog is not ideal for him at all. And the ground at Doncaster last month was pretty badly churned up, too.

Whittling the field down

There are 18 currently in the race and, as well as Cap Du Nord (possibly), I reckon these will also be unsuited by what seems likely to remain heavy ground, and maybe they will not be confirmed on Thursday as a result: Aye Right, Boldmere, Give Me A Copper, Kapcorse, One For Team, Rocky's Treasure, Sizing At Midnight and The Butcher Said.

Of course, I could be wrong - and likes of third favourite, One For The Team, could run regardless - but I am ruling the above nine out of my betting calculations, so that's half the field discarded.

Of the other half of the field, two (Mister Malarky and Yorkhill) are also entered in the Cotswold Chase, so they have got the bullet, too - I don't back or tip horses doubly-entered horses in ante-post races any more, however unlikely their Cheltenham participation may be - and I am quickly down to seven contenders.

Now, I don't know the intended running plans of any of that septet, but I have to take my chances if my earlier analysis is anywhere near the mark, and the three that stand out to me at the prices are Musical Slave at 10/1, and Commodore and Definitly Red at 20s.

Better jumping round key to getting a tune out of Slave

You probably don't need me to tell you that Musical Slave ran a ridiculously eye-catching race at Newbury on his return, when beaten just over 3 lengths into fifth.

To be fair, he made a complete howler at the first there - his jockey did well to stay on - he ballooned the third, was hesitant at a couple more, and he made a hash of the last, so there were extenuating circumstances.

But a better round of jumping and a more positive ride (more of the former, admittedly) would surely have seen him go close to winning there - in fact, I think he would have won - and the 2m4f on good ground that day were nowhere near his optimum conditions.

I appreciate he was withdrawn because of the heavy ground at Haydock last season but that was the going when he improved on all his last three starts of that campaign (it was officially soft when he won at Exeter, but Timeform called it heavy) and he proved he stayed this 3m trip when second to Sam's Adventure at Uttoxeter last March.

The winner went on to beat Sojourn (also a player in here) off a 4lb higher mark this season and unseat when an 11/4 chance in the Peter Marsh on Saturday - he is now rated 9lb higher than for the Uttoxeter win - so I think Musical Slave has a very big shout at the weights here, and in the conditions.

I have no idea if he will run but I think we are looking at a 5/1 chance on the day if he does, so I am happy to back and tip him at 10/1 each-way, four places, with the Betfair Sportsbook.

Red a definite contender if none the worse for recent fall

You have to forgive Commodore a poor run at Kempton last time but the deeper ground here will play to his strengths and he is a fair 20/1+ chance, though I marginally prefer the claims of Definitly Red myself at 26.025/1 or bigger on the exchange.

Anything from 20/1 upwards remains a bet (he is also that price on the Sportsbook) but I will go in win-only as it was a nasty enough fall last time and the stable have not really been really firing of late (though they had a Flat winner 11 days ago).

He has to be forgiven for that fall last time, but that demise in the Rehearsal Chase at Newcastle occurred when he was going well enough in second behind eventual winner Yorkhill, so that is not too off-putting, for all he has a few non-completions on his dance card.

If that Newcastle run was a hint that he was coming back to form - he ran dismally in the Charlie Hall first time up, though he didn't wear cheek pieces there - then he is fairly treated horse, for all a mark of 158 is lofty enough and humping 11st 12lb won't be easy.

However, that is only 2lb higher than when he won at Kelso in the heavy three starts ago in first-time pieces (and he was rated 167 in his pomp), and he has needed his first outing on a couple of occasions in recent seasons. And probably more so now than ever this season as he turned 12yo this year.

He is also one from one at Doncaster, having won a very strong Grimthorpe here by 14 lengths, albeit four years ago now.

With a nod to the favourite and a bow to Commodore at the price, my two against the field are Musical Slave at 10/1 each-way, and Definitely Red at 22s+ win-only on the exchange.

As I have said, I don't know if they are intended runners (and plans change even if they were), but let's hope they both get confirmed for the race on Thursday morning and turn up at Doncaster on Saturday to saturated ground and a single-digit field.

As I have rattled on far too long on one race - though it is always good to be thorough and show your workings - I will end there and return with another ante-post column tomorrow if anything else takes my eye elsewhere.

Good luck.