Key Sri Lankan batsman Kusal Mendis is in doubt for the upcoming two-Test series against Australia after injuring his hand during day one of a tour match.

Mendis was struck directly on the right hand while fielding at short leg in the visitors' warm-up clash with the Cricket Australia XI.

CA XI batter Jake Doran cracked a full toss from tweaker Dilruwan Perera straight at Mendis, who bowed his head and raised his hands in front of his helmet in self-preservation.

The ball smashed into his right paw and the 23-year-old immediately dropped to all fours and writhed on the turf in agony.

Mendis was attended to by medicos from both teams as he left the field.

Vision showed his right pinky finger sticking outwards, prompting fears of a break.

Mendis – who joined Indian star Virat Kohli as the only players to reach 1,000 Test runs in 2018 – would be a massive loss for Sri Lanka.

The right-handed second-drop batsman scored an unbeaten 141 not out versus New Zealand last month, proving he's adept away from the spin-friendly sub-continent.

Mendis also plundered the first of his six Test tons – a mammoth 176 – against Australia at home in 2016.

He wasn't the only Sri Lanka to be hit while fielding on Thursday, either.

Just two balls after Mendis headed to the pavilion for treatment, Doran smacked a ball at Roshen Silva at short leg, who copped a glancing blow to the hand.

The next over, Doran swept in his direction yet again, this time collecting Roshen on the forearm.

After Roshen understandably chucked his helmet to the ground in anger and pain, captain Dinesh Chandimal showed mercy and moved him out of the firing line.

The CA XI lost three early wickets in the opening session, with Test hopefuls Joe Burns, Marnus Labuschagne and Matt Renshaw all departing for single figures.

Potential Test debutant Will Pucovski fared slightly better in making 23 before top-edging a hook to fine leg.

Kurtis Patterson – the only batsman in the CA XI top five who isn't in the 13-man Test squad – compiled a sparkling hundred to get the hosts out of trouble.

All-rounder Doran contributed a classy half-century as the CA XI recovered to 5/228 after 63 overs in the three-day affair under lights, with the pink ball in use.