The Heroes actor will appear in multiple episodes of the Showtime drama as author Ethan Price, Entertainment Weekly reports.
A charming investigative writer, Price will arrive in Miami to research a true crime book about famous murder cases.
Cabrera previously played Isaac Mendez on Heroes between 2006 and 2007 and also played Sir Lancelot on Merlin.
He was recently cast as a series regular on Fox's short-lived sci-fi drama Alcatraz, but ultimately did not appear in the show beyond the pilot episode.
Other stars confirmed to appear in the seventh season of Dexter include Yvonne Strahovski (Chuck), Ray Stevenson (Thor) and Jason Gedrick (Luck).
Strahovski revealed at last week's Dexter Comic-Con panel that her character Hanna is a "woman of mystery with a dark past".
Dexter will return to Showtime on Sunday, September 30 at 9/8c. The show airs on FX in the UK.
> Dexter exec on season seven: 'Everyone's plot is thickening'
Watch the first two minutes of Dexter season seven below: