Al-Nassr suffered a double blow ahead of their next match in the Saudi Roshn League, after medical examinations revealed injuries to their players Mohamed Maran and Saad Al-Nasser.
Both men will now miss training to varying degrees, just as the reigning champions gear up to defend their crown.
Maran's scans confirmed a hamstring tear that will keep him away from training and running for up to six weeks, according to Saudi newspaper Arriyadiyah .
Al-Nasser, meanwhile, picked up a bruise to the ankle joint that will sideline him for a week.
That injury came against Al-Fateh on Saturday in the opening round of the league. Al-Nassr coach Ange Postecoglou was forced to take the Australian off in the 18th minute after he felt pain in the ankle joint.
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Al-Nasser will therefore miss Friday's match against Al-Riyadh. Maran, for his part, got hurt after coming on for Abdullah Al-Hamdan in the 77th minute of that same match.
Preparations for the next fixture resumed on Wednesday, with the players who started against Al-Diriyah put through recovery training.
Postecoglou is expected to start hands-on technical work ahead of the clash with Al-Riyadh, which kicks off at 09:00 pm on Friday (Mecca time) at the Prince Faisal bin Fahd Sports City Stadium in Riyadh, in the second round of the Saudi Roshn League.
Al-Nassr opened their league campaign with a comfortable three-goal win over Al-Fateh. They then followed it up by reaching the round of 16 of the King's Cup, seeing off Al-Diriyah by four goals to one.