Diaz will be called up to the majors on Friday, Jordan Bastian of MLB.com reports.
Diaz appeared in 49 games for Cleveland last season, hitting a mediocre .263/.352/.327. He's hit .284/.415/.375 for Triple-A Columbus so far this year, though he has just two homers in 81 games. He'll likely fill a utility role in his time in the big leagues.