So I've been thinking about spinners.
A mid-20s Nathan Lyon, with a handful of first-class matches under his belt and seemingly little more to offer than Nathan Hauritz, arrived as just the latest guy in a long line of Michael Beers, Xavier Dohertys and Jason Krejzas. Rather than keep chopping and changing, Australia decided to back him. To give him a long leash and trust him with the supporting role to a strong three or four man pace attack. He now has 399 wickets at 32s from 100 Tests.
England had a mid-20s Jack Leach. Unlike Lyon, he had the first-class record to claim with some confidence that he's the best spinner in his country.
Since he arrived he's been dropped variously for Moeen Ali, Dom Bess, Adil Rashid and even Joseph Rootalitharan to act as main spinner instead. Through a combination of this and health problems last winter, he has played only 40% of Tests since his debut. If (big if) he'd played all 40 of those Tests, he'd be sat on about 150 Test wickets at 30 apiece and would be right in the conversation as England's best modern left-arm spinner.
Instead, he's been left out again, for Moeen again, and must be beginning to wonder if his ship has sailed.
What England need to do, ideally with Jack Leach but if that ship sails then with the next spinner, is to just back them. Have them be the fourth/fifth bowler behind Robinson, Mahmood, an all-rounder and a 45-year-old Jimmy Anderson. Tell them that that place in the side is theirs and get them their own coach to work with one-to-one.
It may now be too late for Jack Leach to be England's Nathan Lyon, but it didn't have to be.