The tourists posted 365 for seven to secure a draw, with Joe Root retiring following an untroubled century, but that and question marks over Keaton Jennings and Joe Denly in the top three were secondary to concerns about Nissanka’s well-being.
The 20-year-old was crouching for cover when a powerful Jos Buttler pull thudded into the top of his head, leading to a lengthy interruption in play and an early tea after Nissanka was led from the field on a stretcher and taken to hospital.
Buttler had actually been given out after the ball looped up off Nissanka’s helmet to Angelo Mathews at leg slip, but the England batsman remained in the middle as concerned players from both sides looked on.
Nissanka was said to be conscious as he left the Nondescripts Cricket Club but complaining of neck pain ahead of a planned MRI scan.
Ben Stokes had earlier been forced to retire hurt on 10 when he was hit on the left arm by a Lahiru Kumara short ball.
Nothing more serious than bruising was found and he resumed his innings, adding a further 21 runs before being caught at slip.
With the top of the order, missing the retired Alastair Cook for the first time in 12 years, Jennings batted almost an hour, eking out 13 runs before dragging Shehan Madushanka into his stumps.
Denly’s hopes of making a Test bow didn’t improve much. The Kent all-rounder outscored Jennings with 25 at No 3 but batted awkwardly for much of his 52-ball stay.