What Reece James's surgery does to Chelsea

Reece James is out for several weeks after knee surgery, and Chelsea have set no return date. For a single match that takes a little off Chelsea's chance rather than a lot: one full-back rarely moves a Premier League price by more than a couple of points on his own. What matters more today is that he is one of three Chelsea absences at Everton, and our Desk card already rates Chelsea below the market.

What Chelsea have said

Chelsea confirmed on Friday morning that James had surgery on a knee injury picked up in training the previous week. Xabi Alonso said the operation went well and that "while we don't set timelines, he will be out for several weeks". At his press conference, reported by BBC Sport, he went further: "It's not going to be short. Whether it's before or after Christmas then time will tell." The Guardian's team news lists James out until January.

Emmanuel Emegha felt "a little thing" on Thursday and misses Everton. Jamie Gittens, hurt with England Under-21s, is "still a few weeks" away.

Why a full-back moves a price less than you think

A bookmaker's price on a club like Chelsea is built on the squad, not on the eleven names on the sheet. Alonso said it himself: Chelsea "have a big squad to deal with injuries". There is cover at right-back, the system barely changes, and the market moves a little.

Where an injury moves a price more is when it stacks. James plus Emegha plus Gittens is a captain, a striker option and a wide forward gone in the same week. Each one is small. Together they thin the bench, and the bench is what a deep side leans on in the last half hour.

What our number says

The Desk card for this lunchtime's game has Everton 41.3%, the draw 25.7% and Chelsea 33.0%. The best Everton price we saw was 3.30 at Betfair, quoted at 04:21 UTC, against our fair 2.42: an 11.0 point edge. The full card and what else moved it are in Everton v Chelsea prediction and odds. How we think about an absence in general is in what Milenković's absence does to Forest.

We cannot split our number into "this much for James, this much for Everton's form". The research runs on the whole picture. What we can say is that the injury news points the same way as our number, which is not proof that the number is right.

What this does not tell you

It does not tell you how long James will really be out; Chelsea will not say. It does not price any game beyond today, and it does not account for how Everton's own doubts (Branthwaite, Mykolenko, Nørgaard) resolve by kick-off. Injury news is one input among many, and the market has read the same press conference we have.