Sri Lanka captain Angelo Mathews has added his voice to the growing din of international players and captains who have questioned the new ODI rules. Last month, MS Dhoni suggested the current playing conditions reduced bowlers to little more than bowling machines, with team-mate Suresh Raina also expressing a similar sentiment.

Last year, then-Sri Lanka captain Mahela Jayawardene had been critical of the rule restricting the number of outfield fielders to four during the non Powerplay overs, as well as the rule that requires teams use a new ball from either end. He reasoned that spinners would end up having to bowl defensively, or risk becoming extinct in 50-over cricket, and that reverse-swing had also largely left the one-day game.

Unlike in India, where totals have grown considerably in the year since the new rules were instituted, team scores in Sri Lanka have been roughly moderate, but Mathews lamented the difficulties for bowlers ahead of the third ODI against New Zealand in Dambulla.

"The bowlers might retire very soon, the way the rules are going," Mathews said. "With the fielders inside the circle, it's very hard for the bowlers. I feel for them. With these rules, with the two new balls, it's very hard for the spinners. You have to be a very good spinner to get away from the batsman. You can't go in with half-bowlers."

"Now as a bowler, you've got to think a step ahead of the batsman. You have to anticipate what he's going to do, but you can't also pre-plan - you have to wait till the last moment for the batsman to do something and then react. You might go up to the mark and think you're going to bowl a yorker, but you might have to change that in the end. Even in the delivery stride, you might have to adjust. So you have to bowl according to the batsman. "

Mathews also suggested his team would make two changes to the XI as they seek to level the three-match series. Sri Lanka have lately followed a policy of providing young batsmen ample opportunity before discarding them, but opener Dimuth Karunaratne is unlikely to benefit from that largesse in ODIs after a first-ball duck and a four, in the two matches so far.

Sri Lanka have searched all year for the opening batsman who might partner Tillakaratne Dilshan in the 2015 World Cup, but despite two young candidates having impressed in patches - Karunaratne and Kusal Perera - neither batsman could sustain their success. Jayawardene has often moved up the order when the second opener has failed, and though he thrives atop the order, he has had to move back down to No. 4 to bridge gaps in the middle order.

"We've been trying to get an opener for a while now. We've opened with Mahela and Dilshan, we've opened with Kusal Perera and Upul Tharanga as well. It hasn't worked for us, so the selectors thought they'd try out Dimuth Karunaratne as well, because he's scored a lot of runs in the A team. Unfortunately he failed in the first two matches, so it might be a different combination tomorrow."

Kusal is in the squad for the series but Mathews refused to reveal which opening combination Sri Lanka might employ. Aside from Karunaratne, Perera and Jayawardene, Lahiru Thirimanne is also capable of opening, having performed the role for his domestic teams as well as for Sri Lanka in Tests, the latter albeit unsuccessfully.

The second likely change for the match is allrounder Thisara Perera's inclusion, after he had been left out for the first two matches. After having been an ODI regular for over a year, Perera had a somewhat unsteady few months with selection. He had been left out from Sri Lanka's ODI tri-series squad to the West Indies, but played well at home against South Africa in the series that followed.

"Thisara is a match-winner and we need to find a way to bring him back to the team. In the South Africa series we rotated the seniors, but we will play our best available team tomorrow. Whether Thisara will come in in place of another bowler or another batsman - we're not yet sure. We'll have to take a call on our exact combination after having another look at the pitch."

Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. He tweets here