Jason Gillespie believes Adil Rashid can use his disappointment at being dropped for England's tour of South Africa to become a better player.
The Yorkshire leg spinner was left out of the touring party for the four-Test series despite taking a lead role during their recent matches with Pakistan in the United Arab Emirates.
Rashid failed to have the impact some would have liked in those three games – he took eight wickets at 69.50 – and was not selected to travel to South Africa, Moeen Ali taken as the lead spinner with Samit Patel as back-up.
As a result Rashid has been allowed to follow Gillespie to the Adelaide Strikers in the Big Bash League, and his coach feels it could be the perfect opportunity for the 27-year-old to develop his game.
"I certainly believe he's in the best England squad for Test cricket on form," Gillespie told reporters.
"But all the words we're hearing is that, with the conditions in South Africa, that it's very unlikely England will play two spinners and they've weighed up what would be better.
"If he's not going to play would he be better served with this opportunity in the Big Bash and playing some cricket leading into some of the challenges England have got in the shorter form of the game or carrying drinks around SA?
"The England management have made that call and I think it's a good decision. You would rather have a player playing than just wearing a bib and carrying drinks around."
While some criticised Rashid for his displays during the Pakistan series – which England lost 2-0 – Gillespie still believes he is the best slow bowler England have at their disposal.
He added: "I thought there were times when he was a bit inconsistent, but I think he got better as he went along.
"I felt there was an improvement there and his consistency did improve. I think Adil will have learnt a lot, how to play to certain players, certain lines and lengths, and he will be a better player.
"I certainly think he could do that job [as main spinner] but at this point in time it appears England don't quite see that yet.
"They are happy with his progress, it was a tough tour to UAE to play Pakistan, but he is and will be a better bowler for that experience."