The 26-year-old batsman, famed for his powerful strokeplay, will be added to the current 14-man squad that is playing a two-match Test series against Sri Lanka.
The addition of just one name to the squad dashed hopes that some of the 10 leading players who refused to sign tour contracts for the Tests due to a sponsorship dispute may reach an agreement with the cricket board in time for the tri-series.
The tri-series, which also includes India as well as hosts Sri Lanka, starts in Dambulla on July 30.
Powell will add valuable experience to the squad having played 105 one day internationals, scoring 2,070 runs at an average of 25.87 during his career.
Full squad
Shivnarine Chanderpaul (captain), Ryan Ramdass, Xavier Marshall, Sylvester Joseph, Runako Morton, Narsingh Deonarine, Denesh Ramdin, Omari Banks, Tino Best, Daren Powell, Jermaine Lawson, Ricardo Powell, Dwayne Smith, Kerry Jeremy, Deighton Butler.
