England have made one tough call for the must-win Sharjah Test, but will leave a potentially even trickier one until the last minute. Alastair Cook admits it was "not much fun" having to tell out-of-form wicketkeeper Jos Buttler he was being dropped as England try to battle back for a 1-1 series draw in the final match of three.

More enjoyable was informing James Taylor he will finally get another chance in England's middle order - more than three years after he was cast aside following two Tests against South Africa.

But Cook and coach Trevor Bayliss must still decided whether they bring in a like-for-like replacement for rested seamer Mark Wood. Liam Plunkett is the obvious first port of call ahead of Chris Jordan - or they could take a punt on conditions and recall all-rounder Samit Patel as a third spin option.

The stakes are high, and it could become all too obvious very quickly if England go the wrong way at a noted spin-friendly venue. In a series where the tourists' seamers have so far consistently outbowled spin twins Adil Rashid and Moeen Ali, Patel is still the left-field selection.

"That's the major decision we have to make," said Cook. "It will be really easy after the game in hindsight to see whether we've made the right decision - but it will be a tough call."

Cook is much more convinced of Taylor's renewed credentials as a Test match batsman. Asked if the 25-year-old is ready to return, he said: "I firmly believe he is. I'm sure he feels he was harshly treated ... sometimes that's the way of selection.

"But he's gone away over the last three years, and he's a lot different player than what I remember him as.

"He's itching to play, and you don't average 47-48 in first-class cricket without being a fine player."

England have been persuaded by Taylor's adaptability against spin, and determination to make the most of an opportunity once he is set.

"One of his very strong points is that when he gets in he goes on to get big scores," added his captain.

"We know how important first-innings runs are to set the game up."

While Taylor comes back in from the cold, Buttler is at a career crossroads.

Jonny Bairstow will take over the gloves, with Buttler's absence opening up the place for Taylor in what will be a rejigged middle order below the prolific Joe Root at number four.

It fell to Cook, of course, to confirm to Buttler what he had surely already guessed after a miserable run of form with the bat.

"Telling him was part of the job that is not much fun," he said.

"He's clearly struggled for runs in the last six months or so.

"He'll have to go away and be really clear on how he wants to play in Test cricket.

"He knows his game really well in Twenty20 and one-day cricket, but he probably knows it less well Test cricket.

"It's about finding his ideal method and sticking by that."

Cook suggested Buttler could do worse than following the example set by Root, who was dropped after the 2013/14 Ashes but now sits atop the global Test batting rankings.

"We all know the amount of talent (Jos) has got - you see him play an innings that everyone around the world says is amazing - but he's not the first person who has come in, done pretty well then had a tough patch, been left out and come back stronger," Cook said.

"He only has to look at Joe, getting left out of that Sydney game and using it as motivation to be clear on how he wanted to play in every situation.

"He's come back as a far better player because of it."

Pakistan captain Misbah-ul-Haq, meanwhile may be double-bluffing England with his assertion that Sharjah will be no place for three spinners in the final Test.

Misbah offered no clear guidance to the tourists at his captain's press conference when he hinted Pakistan have been dissuaded from picking an extra spinner themselves - by the evidence of their own eyes.

They have the option of replacing seamer Imran Khan, who split the webbing on his bowling hand in practice, with uncapped Bilal Asif - the off-spinner cleared of a suspect action only 24 hours previously by International Cricket Council testing.

Yet Misbah, doubtless aware England too must make a similar selection call, publicly veered away from the notion of picking just one seamer.

As well as being one up with one to play, of course, Pakistan's position of strength stems further from the knowledge their two spinners - Yasir Shah and Zulfiqar Babar - have been more effective than England's in the first two Tests.

Misbah implied the Sharjah surface is a step into the unknown for both sides.

"They have changed the upper layer of the pitch, so we don't know too much about it," he said.

"Let's hope it spins.

"We have been thinking about it, but the pitch doesn't look like that sort of a turner where you can go with three spinners.

"That's our thinking at the moment."

Bilal appears to be a long-term, rather than immediate, option - after proving his arm is sufficiently straight in delivery.

"We are happy about that, because we don't have any other [frontline Test class] off-spinner in Pakistan," said Misbah.

"He took five one-day international wickets in Zimbabwe, so we're thinking we've got a spinner we can rely on and work with in the future.

"He is young and can bowl and bat a bit. That could really help Pakistan cricket."

Misbah has been able to confirm "key batsman" Azhar Ali, finally available after missing the series so far with an infected foot and then after the death of his mother-in-law, will return in Pakistan's top three.

No matter how England fare over the next five days, Misbah insists they are currently better equipped for Test cricket in the desert than Australia were on the way to series defeat here a year ago.

"I think you can clearly say they are better side than the Australians in these sorts of conditions," he said.

"You have to give credit to England - the way they are applying themselves."

The 41-year-old suggested before the start of this series that it may be his last.

That could still be the case, but the inscrutable Misbah will be announcing nothing just yet.

"There is plenty of time before the next series, so I'm taking more time to make a decision - and will give it some thought," he said.

"I was trying to make a decision before this Test - but I've left it, and will have another think (later)."