Hetmyer and Evin Lewis were spectacularly dropped after an announcement they had both failed fitness tests Cricket West Indies selectors had implemented as a requirement for selection.
There is still no recall for Lewis, who had, not long before, overcome poor form in typically destructive fashion.
The squad also includes a recall for Andre Russell and Oshane Thomas.
Allrounder Russell, 31, hasn't played for the Caribbean side since pulling up short midway through the 50-over World Cup in June 2019. However, he has taken part in other matches, most notably in the Bangladesh Premier League in December and January
Russell is a two-time ICC T20 World Cup winner, having played a crucial role in the triumphs back in 2012 in Sri Lanka and 2016 in India. He has successfully completed the Cricket West Indies (CWI) return-to-play assessment programme under the supervision of CWI Medical Team in his native Jamaica. He has so far played 47 T20Is for the West Indies.
Fast bowler Thomas, who turned 23 earlier this week, is selected after making a full recovery from a car accident in Jamaica recently. Additionally, wicket-keeper/batsman Shai Hope has been included alongside left-arm spinner Fabian Allen.
Commenting on the squad, CWI lead selector Roger Harper said: “Shimron Hetmyer missed out on selection for the ODI squad. He has since attained the required fitness level, becoming available for selection and has been included.
"Andre Russell is back in the squad, having been cleared by the medical panel and successfully completing CWI’s return-to-play protocol. Andre will add potency to every department of the team. Oshane Thomas appears to be focused and raring to go. He will add pace and penetration to the bowling unit.”
Harper added: “Shai Hope provides an opening option and cover as a back-up wicket-keeper also. Fabian Allen returns from the injury he sustained in the series against Afghanistan late last year. He will provide a spin-bowling option as well as adding depth to the batting group.”
Looking ahead to the T20I matches, Harper outlined that he will have one eye on the ICC T20 World Cup to be played in Australia later this year. West Indies are the defending champions and the only team to lift the trophy twice.
“I look forward to the team building on its recent performances and winning the T20 series in Sri Lanka. This is another opportunity for the team to build on its strengths and identify areas that need improvement while continuing the process of building up with the aim of peaking for the T20 World Cup in October,” said Harper.
The two T20Is will be played at the Pallakele International Cricket Stadium in Kandy.
West Indies and Sri Lanka are now contesting a three-match ODI series. Sri Lanka won the first match today by a wicket in Colombo.
The second match is in Hambantota on Wednesday.
West Indies T20I squad
Kieron Pollard (capt), Fabian Allen, Dwayne Bravo, Sheldon Cottrell, Shimron Hetmyer, Shai Hope, Brandon King, Nicholas Pooran, Rovman Powell, Andre Russell, Lendl Simmons, Oshane Thomas, Hayden Walsh Jr, Kesrick Williams.
IN: Andre Russell, Oshane Thomas, Fabian Allen, Shai Hope.
OUT: Evin Lewis, Khary Pierre, Sherfane Rutherford, Romario Shepherd.