Smith-Njiba signed a minor-league contract with the White Sox on Aug. 7 and debuted with Double-A Birmingham on Tuesday, going 2-for-3 with a solo home run.
Smith-Njigba was released by the Pirates on Saturday, per MiLB's transaction log.
Smith-Njigba cleared waivers and was outrighted to Triple-A Indianapolis on Saturday.
The Pirates designated Smith-Njigba for assignment Thursday.
The Pirates optioned Smith-Njigba to Triple-A Indianapolis on Tuesday.
The Pirates claimed Smith-Njigba off waivers from the Mariners on Monday.
The Mariners designated Smith-Njigba for assignment Saturday, Ryan Divish of The Seattle Times reports.
The Mariners claimed Smith-Njigba off waivers from the Pirates on Wednesday.
Smith-Njigba was designated for assignment by the Pirates on Wednesday, Jason Mackey of the Pittsburgh Post-Gazette reports.
Pittsburgh optioned Smith-Njigba to Triple-A Indianapolis on Wednesday, Justice delos Santos of MLB.com reports.