Sri Lanka duo in wickets against Northamptonshire
Sri Lanka's Mahela Jayawardene (front) playing a sweeep past England wicket-keeper Jos Butler during the fifth one-day international in Birmingham, central England on June 3, 2014 - by Andrew Yates
Northamptonshire, at tea on the second day of four at Northampton, were 65 for two in reply to the tourists' 558 for eight declared.
After Lahiru Thirimanne, Sri Lanka's captain for this match in place of the rested Angelo Mathews, called a halt to an innings where he made a career-best 156, his side did not have long to wait for a wicket in their final match before the first Test against England at Lord's on Thursday.
Welegedara had James Kettleborough lbw for a golden duck on the opener's first-class debut, with a ball that nipped back.
And the impressive Pradeep took his 100th first-class wicket when he had Northamptonshire captain Stephen Peters caught behind with a lifting delivery to leave the hosts 32 for two.
But South Africa's Richard Levi kept Sri Lanka at bay with an unbeaten 53 including nine fours.
Sri Lanka were 358 for three overnight but before play resumed Friday, opener Kaushal Silva retired on 152 not out with what tour officials said was a stomach illness.
Silva batted for just over six hours, facing 260 balls with 21 fours and two sixes.
Together with Thirimanne he'd put on 238 for the fourth wicket.
Left-hander Thirimanne resumed on 120 not out, having been dropped off his first ball Thursday by wicketkeeper Ben Duckett.
Northamptonshire, struggling at the foot of the First Division of the County Championship table with five defeats from six matches, rested several players from the side that suffered a 271-run thrashing by Yorkshire in their last first-class match.
Among those missing were former South Africa all-rounder Andrew Hall, Pakistani seamer Mohammad Azharullah, New Zealand paceman Ian Butler, and fast bowler Maurice Chambers.
Thirimanne was in complete command as he drove a full-toss from medium-pacer Kyle Coetzer down the ground for four.
He then surpassed his previous first-class best of 155 not out, made against Bangladesh during a Test in Galle in March last year.
But on 156 he was bowled trying to slog-sweep left-arm spinner Matthew Spriegel.
Thirimanne batted for nearly five hours facing 221 balls including 14 fours and two sixes.
Spriegel then had a personal return of two wickets for no runs in eight balls, as Sri Lanka's 441 for four became 442 for five, when he bowled Dinesh Chandimal on the sweep for 47.
But Dilruwan Perera, primarily a slow bowler, launched expensive left-arm spinner Graeme White (none for 129) for two sixes.
Perera went to a 63-ball fifty with a six, four and a six off three successive deliveries from part-time spinner Rob Keogh.
However, Keogh did have Prasanna Jayawardene well caught in the deep by Levi before Perera holed out for 59 to mid-wicket off Steven Crook.
Seam bowler Crook led Northamptonshire's weakened attack with three for 98 in 27 overs.