Zgonina played collegiately at Purdue, and he was the Big Ten Defensive Player of the Year as a senior.
Zgonina signed a four-year contract that reportedly included a $500,000 signing bonus.
In other news:
-- The Dolphins began their offseason workout program on Monday and although exact numbers weren't provided, participation once again is expected to be excellent.
-- The Jacksonville Jaguars announced that their preseason game against the Dolphins has been scheduled for Friday, Aug. 15 at 7:30 p.m. The Dolphins also will play Atlanta Aug. 21, while exact dates for games against Tampa Bay and New Orleans haven't been determined.