Sarfraz was hit on his left forearm by a Mitchell Starc short ball when he was on 90, in the 70th over of Pakistan's innings. After getting some treatment, he batted on for a couple of overs before holing out off Marnus Labuschange for 94.
He then kept wicket for the seven overs Australia batted, not looking comfortable, but still taking an excellent, diving leg-side catch to dismiss Usman Khawaja.
When he turned up at the end of the day to speak to media, it was with an icepack strapped to his left forearm.
"The arm is not moving properly," he said. "It's a bruise, but I think it will have swelling later. I think Mickey [Arthur] was talking to the umpires about a reserve wicketkeeper tomorrow. That time when I was hit, I felt pain, but I hung on because I was approaching my century.
"I think had it been more forceful, then I would not have been able to bat properly after that, but I hope that with icing, it will get better."
The MCC, guardians of the Laws of Cricket, last year introduced a rule confirming that substitute fielders will be allowed to keep wicket should the original wicketkeeper suffer an injury during play. The umpires have to okay the change, and it is understood that match officials will allow another wicketkeeper should Sarfraz not be able to come out.
That will be Mohammad Rizwan, who was part of the original 18-man Pakistan squad for this Test series. Rizwan was released before the second Test and allowed to join the Pakistan 'A' side, also in the UAE, to take on New Zealand 'A'. That, however, is believed to not be an issue in allowing Rizwan to take over.
In the ICC's Test match playing conditions, clause 1.2.1 states that each captain can nominate up to six substitute fielders on the team sheet handed to the match referee before the toss.
Whether or not Rizwan's name was on that team sheet - as he had been released - is a point made moot by clause 1.2.2, which says: "Only those nominated as substitute fielders shall be entitled to act as substitute fielders during the match, unless the ICC Match Referee, in exceptional circumstances, allows subsequent additions."
Pakistan are fortunate in having Rizwan, who has played one Test, available in the first place. The usual practice, under Sarfraz's captaincy, has been to not pick a back-up wicketkeeper in their squads. But a lack of form and concern over Sarfraz's excessive workload meant Rizwan was selected.
In the event that Sarfraz doesn't show up, Asad Shafiq will lead Pakistan on the field.
Osman Samiuddin is a senior editor at ESPNcricinfo