Australia spinner Steve O'Keefe will return home due to his hamstring injury, with Jon Holland called up as his replacement in Sri Lanka.
O'Keefe, 31, suffered the injury during the first Test in Pallekele on Thursday, seemingly bringing an early end to his tour.
Australia physio David Beakley is unsure how long O'Keefe will be sidelined, but said it was unlikely he could return in time for the last two Tests.
"Initial assessment indicates a moderate grade hamstring injury which means it is highly unlikely that he will be available for the remainder of the Test series," he said.
"Steve will remain with the squad in Kandy until the end of the Test and will undertake imaging on the injury upon his return to Australia."
Holland will join the squad and is almost certain to make his international debut in Galle starting August 4.
The 29-year-old played just two Sheffield Shield games for Victoria last season, having been behind Fawad Ahmed in the pecking order.
Australia national selection panel chairman Rod Marsh believes Holland will settle well and is almost certain for a debut in the second Test.
"It is incredibly disappointing for Steve to get this injury and I really feel for him," he said.
"He was bowling well in the Test and had caused some trouble to Sri Lanka's top order.
"The selectors have decided to go for a like-for-like replacement for Steve, in Jon Holland.
"Jon had a good end to the Sheffield Shield season and is currently in Brisbane with Australia A as they prepare for a four-day match against South Africa A.
"He will be on a plane as soon as possible and is a strong chance to make his debut in the Galle Test."
Sri Lanka hold a 196-run lead with four wickets remaining in their second innings.