The White Sox selected Montgomery's contract from Triple-A Charlotte on Tuesday.
The 23-year-old is one of the top prospects in baseball and is now set to make his major-league debut for the White Sox. Montgomery opened the campaign with Double-A Birmingham and posted a 1.035 OPS in 27 games before being promoted to Triple-A in early May. Montgomery then had an .864 OPS in 28 contests for Charlotte, and Chicago is now ready to give him a look in the big leagues. He's played both center and right field this season and should see plenty of playing time between those two spots for the White Sox.