Stokes, 24, who hit a fifty and took four wickets in the drawn first test, training on Tuesday was lost, but take part in a network later on Wednesday.
Captain Alastair Cook said he was not sure he would play Stokes, adding that it was "not at all" on Tuesday.
"In these conditions, a large amount of energy is needed for maximum efficiency "Cook said. "You have to be careful."
Cook added that he thought Stokes "should be fine," but that they would take the final decision on Thursday morning.
If Stokes, who has played in the last 11 matches of England, is not available, Samit Patel road could enter to give Cook a third spin option.
Patel played the last of his five events in 2012.
"We said at the start of the tour if the gate requires three spinners, will play three spinners," Cook said.
"We have that option and we would not really affect the balance of the side as all three of our spinners can bat."
England prepares to test for Yasir
Pakistan is expected to have the leg-spinner Yasir Shah as after the first test was lost with back spasm.
Yasir, 29, has taken 61 wickets in just 10 Test matches since making his debut against Australia last year and is fifth in the Test bowling rankings International Cricket Council.
"Obviously we have clearly videos and a couple of the guys you've faced in a game day,"Cook said.
"One time a guy loose the ball does not come down with a name on it, just react to it and make sure you are clear about how a leg-spinner is played.
"He is a very good bowler, but this is not superhuman guy who takes a wicket every time he bowls."
Pakistan captain Misbah-ul-Haq believes Yasir will have a "huge impact" if he plays.
"Over the past year has been excellent and he is the player bowling highlight for us," he said. "He creates a lot of pressure and we'll be really sure if back in the side."
Suspect bowler loophole 'strange'
Asif Bilal is yet to play a test, but has appeared in two one-day internationals this year
Pakistan also recalled off spinner Asif Bilal - which was reported for suspect bowling action against Zimbabwe earlier this month - as cover.
Asif, 30, is allowed to play pending a report on its performance, which is expected to be completed in two weeks.
"I think it's a little strange to be honest," Cook said. "Once it has been reported, you would expect from a system is in place it fast.
"But that's just the way it is and if that's what we have to face, which is what we have to face."
Misbah said Pakistan had no concerns about Asif action - and he is firmly in contention for selection.
"Not a problem for us," he said. "If he is here, we are confident enough to pick it up for the exam."
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