Both players had been named in the travelling squad, but the selectors were concerned with their match fitness. However, following an eight-day training camp, SLC now believe both players will be ready for the first Test in Port of Spain from June 6.
Mathews last played for Sri Lanka in an ODI against Zimbabwe in Dhaka in January, where he aggravated a recurring hamstring problem. That resulted in him missing the remainder of the Bangladesh tour as well the Nidahas Trophy in March, before returning to domestic action last month.
Lakmal, meanwhile, has been in and out of the side in recent times, either through injuries or due to selectors managing his workload. The 31 year-old fast bowlerwas rested for most of the Nidahas Trophy, after which a side strain ruled him out of last month's Super Provincial four-day tournament. He has since returned for the Super Provincial Limited Overs matches.
Lakmal's return strengthens a depleted Sri Lankan fast bowling line-up, with Lahiru Gamage, Lahiru Kumara, and the uncapped pair of Asitha Fernando and Kasun Rajitha the only other quicks on tour.
Mathews may have been expected to share in the workload but SLC confirmed to ESPNcricinfo that 30 year-old will only be used in his capacity as a batsman, while Lakmal's workload too will be managed on a game by game basis.
"Mathews will not be bowling, while Lakmal's inclusion [in the third Test] will depend on how much he bowls in the first two games," said Chief selector Graeme Labrooy. "That however depends on the selection committee on tour, and how much of a workload he undertakes."