Chris Cotillo of SB Nation first reported the Padres and Chicago White Sox had agreed to a deal with Shields as the centerpiece. Dennis Lin of the San Diego Union-Tribune confirmed the move, adding that Fernando Tatis Jr. and Erik Johnson would go back to San Diego.

Lin had previously reported the Padres and White Sox were in advanced talks, with Shields expected to be dealt before his start against the Colorado Rockies on Sunday.

Lin first reported on May 28 the teams were engaged in discussions about Shields. 

The Padres had been looking to trade Shields basically from the moment they signed him in February 2015. He was supposed to anchor their rotation after general manager A.J. Preller traded for Justin Upton, Matt Kemp and Wil Myers to bolster the lineup. 

Instead, San Diego never found its footing, and Shields endured one of his worst seasons in 2015. The right-hander did have 216 strikeouts in 202.1 innings, but he tied Kyle Kendrick for the most home runs allowed (33) in the majors and walked a career-high 81 batters. 

Shields has a 4.28 ERA with 57 strikeouts and 27 walks in 67.1 innings this season. He is being paid like a front-line starter, but he's pitching more like a No. 3 or 4 option.

The White Sox are a logical fit because they got off to a strong start and have two workhorses in Chris Sale and Jose Quintana at the top of the rotation but not much depth after that. Shields could slot in behind them without needing to be the face of the staff.