Let us look at the Test records for most runs in a career first:
Now look at the current statistics of(as on January 2016):
Cook is 31 years old already, and is still another 5,967 runs behind‘s total. Let’s do some basic math here. Cook scores around 79 runs per test on an average. He will need to play another 77 tests at the same average or better, to surpass 15,921 runs. Now, Cook has been playing since 2006. He has played 12 tests per year on an average. He will take at least 6 more years to play those 77 tests needed, at which time he will be over 37 years old. He would also be playing over 200 test matches en route.
Theoretically possible. Statistically improbable. Practically not possible. English batsmen typically do not last that long. If Cook does manage this i.e. play till 2022 and beyond, he will be the first rare exception. But I, personally, don’t see it happening.
There is no current player in the near vicinity who can threaten this record. Sachin Tendulkar‘s record for most runs in Tests will not be broken for a long, long time. At least not before 2022, like we just analysed, that is for sure.
In fact, Tendulkar’s record for most centuries in Tests is safe as well.
Doing the same math, I can say Alastair Cook will not go beyond 45 centuries.
Update (11 September 2018):
Alastair Cook retired from international cricket today. Since I published this blog post two and a half years ago, Cook has scored 2,518 runs and 5 centuries in 35 matches in this time. He managed to move up to 5th in the list of all-time highest run-getters, but Tendulkar’s record remains unbeaten. Cook was 3,449 runs and 18 centuries behind Tendulkar at the time of his retirement, and there was no way in the world he would catch up to him even if he played those additional 39 test matches.
That being said, due credit to a fine batsman. England’s greatest. #ThankYouChef