Pakistan suffered an injury scare on the eve of the first Test after Yasir Shah went down with a back problem in training. Captain Misbah-ul-Haq said he had experienced a back spasm and an assessment would be made in the morning.

Yasir was bowling in the nets and collapsed after catching his studs in the turf. He was left lying on the ground in apparent pain before being helped away by fellow spinner Zulfiqar Babar.

The legspinner, who recently became the fastest Pakistani to 50 Test wickets, has been viewed as one of the key bowlers in the series and his absence would be a significant blow for Misbah's side. Pakistan's No. 3, Azhar Ali, has already been ruled out with a foot injury.

"We want to wait until tomorrow and hoping for the best," Misbah said. "He got a back spasm and let's see [how his recovery goes] overnight. His loss could be a big blow but we are hoping that he will be a fine as he is our key player and we are very much concerned about him.

"Obviously we are looking into it [a replacement]. In case if he won't recover then we need to have someone and we are working on that. Hopefully we will get someone for tomorrow morning.

"Considering the injury to Azhar Ali, now if Yasir couldn't make it it will be a tough challenge for us. It will be hard for us to cope without him but this is exactly the same scenario, we are already playing against a top team and we knew we have to come hard so it will be more challenging."

Pakistan have called up left-arm spinner Zafar Gohar, who played against England in their two warm-up matches last week. Gohar had returned to Pakistan and is unlikely arrive back in the UAE before the start of the Test on Tuesday, which means Pakistan may have to resort to playing another pace bowler if Yasir is unfit.

Chief selector Haroon Rasheed told ESPNcricinfo: "Team management required a replacement as a precaution and we are making sure that a player should be sitting on bench before the Test match starts."

Courtesy Cricinfo