Pillar went 3-for-5 with one RBI and one run scored in Tuesday's 7-6 loss to the Cardinals.
Pillar went 3-for-4 with a triple, three RBI, two runs scored and a stolen base in Saturday's win over Kansas City.
Pillar went 3-for-5 with two home runs and six RBI during Tuesday's 9-0 win over the Pirates.
The White Sox designated Pillar for assignment Friday, Ken Rosenthal of The Athletic reports.
Pillar is not in the lineup for Saturday's game against the Tigers.
Pillar signed a major-league contract with the White Sox on Sunday.
The White Sox released Pillar on Friday.
Pillar signed a minor-league contract with the White Sox on Friday.
Pillar will start in left field and bat second in Wednesday's game against the Mets.
Pillar hasn't started a game for Atlanta since June 20, seeing just six plate appearances since.