You might have heard that James Anderson is 39. That’s old for an active Test cricketer, and almost unheard of among fast bowlers. Of the 10 players aged 39 or more to play Test cricket this century, Anderson is the only seamer. Only five seamers in the history of Test cricket have bowled more deliveries than Anderson after turning 39; his longevity is extraordinary.

On the surface, there has been no obvious dip in his output. His pace is still in the mid-eighties – remarkably, he was England’s fastest bowler at Headingley – and he’s still very much the leader of the attack. He has played 10 of England’s 12 Tests in 2021 and has averaged a lowly 23.40. His economy rate this year (2.21) is the lowest it’s ever been in a calendar year and with new additions in his armoury, there are times where you wonder if this is the best he’s ever been.

But age catches up with everyone. There will be a point, as terrifying as it may be to England supporters, where bowling 50 overs a Test at 100 per cent will probably be beyond Anderson. There is a chance that we’re already there.

A somewhat alarming stat has been doing the rounds. Since the start of the 2020 home summer, Anderson averages over 100 with the ball in the second innings of home Tests over 10 Tests against four different opponents. On the flip side, he averages 19 in the first innings over that same period. There is a rather sizeable gap of 80 runs per wicket between the two innings. What’s behind it?

Luck surely plays a role. Luck has a more prominent role in the game than we like to admit. Marginal decisions where you miss out on an lbw by a hair’s width and dropped catches are out of a bowler’s hands. According to CricViz, Anderson’s expected average is only marginally higher in the second innings compared to his first innings efforts.

Then there’s the nature of some English pitches. Part of what makes Test cricket in England so entertaining is how they fluctuate over the course of five days. Batting is often easiest on days three and four, the times you’re most likely to be bowling your second innings.

Bizarrely, Anderson’s away second innings average over the same period is 15.50, albeit from a much smaller sample size of four innings. In that time, he has taken three wickets in an innings once, his match-winning 3-17 at Chennai.

It is fair to ask how much of a toll his first innings workload has on what he’s capable of in his second innings. Going back Test by Test to the start of the 2020 summer, there are a few patterns.

3-62 (25) & 0-42 (15)
2-28 (16) & 0-18 (8)
1-63 (19) & 0-34 (9)
3-60 (27)
5-56 (23) & 2-45 (19)
6-40 (29) & 0-6 (2)
2-46 (16.5) & 3-17 (11)
0-20 (13)
3-44 (25)
2-83 (28) & 0-44 (15.3)
1-68 (29) & 0-11 (5)
4-54 (23) & 0-12 (5)
5-62 (29) & 0-53 (25.3)
3-6 (8) & 1-63 (26)
1-41 (14) & 1-79 (33)

One, Anderson’s first innings consistency is absurd. Second, on the seven occasions that he bowled 20-plus overs in the first innings and bowled second innings overs, he has take a wicket just once second time round. Third, it is still a pretty small sample size; in five of his wicketless second innings efforts, he bowled fewer than 10 overs across the innings.

It’d be a bit reckless to make too firm a conclusion on Anderson’s second innings’ effectiveness, but equally itwould be a bit one-eyed to presume there’s nothing in it at all. The margins in Test cricket are so small that even a barely noticeable drop in pace or energy behind the ball could have a significant impact on overall output.

He is so devastating in first innings that his value to England is still astronomical, but it does give a small glimpse into what life after Anderson could look like. In those second innings, others need to carry more of the load. Ollie Robinson has done that superbly this summer and at The Oval today, there were times where Woakes in particular looked threatening. But it’s on days like this, on flat pitches, when Anderson is not quite 100 per cent, with Broad injured and without an out-and-out quick, England can look bereft of ideas. There were times on day four where Root seemingly had more faith in his part-time offies than he did in Craig Overton who was under-bowled after a disappointing outing on day three.

Replacing Anderson will be a near-impossible job, and it’s one that England won’t want to think about if they don’t have to. But at some point it will become necessary, and, if nothing else, Anderson’s second-innings struggles should give a nudge that one day, England will have to make do without. His first-innings success, however, at least provides hope that there’s still a while left of him yet.