Perera was clearly struggling with his hamstring while running between the wickets during his innings, in which he top-scored for Sri Lanka with 39. Dr. Daminda Attanayake, a team physician, told ESPNcricinfo that Perera's availability for the World Cup was "on the fence", and that the medical team might have a clearer idea of his prognosis after further observation and testing, which should occur by September 23.
"The inury is a sprinter's injury, which can be picked up while running between the wickets," Attanayake said. "Because of the nature of the injury we can't do a fast rehabilitation."
Perera has had long-standing problems with his hamstrings, though this particular injury is not understood to be a chronic overuse injury. He had just come back to international cricket after having recovered from Covid-19, and had also missed India's tour of Sri Lanka with an injury.
Madushanka, who was playing his third T20 International, hurt himself while making a diving stop in the outfield. He landed hard on his left shoulder and was seen reaching for it in discomfort immediately. Sri Lanka will be required to name a replacement for him in the World Cup squad.
If it turns out Perera is unavailable for the World Cup, Sri Lanka will be without perhaps their best T20 batter. He has 1416 runs at a strike rate of 132.21 in the format.
Sri Lanka are required to play the qualifying round of the World Cup if they are to move on to main draw. They play Ireland, Namibia and the Netherlands in their qualifying group.
Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. @afidelf