The 6-foot-3, 215-pound Shields has gone 129-104 with a 3.76 ERA (910 ER/2,180.0 IP) and 1,899 strikeouts in 330 career games (329 starts) over 11 major-league seasons with Tampa Bay (2006-12), Kansas City (2013-14) and the Padres (2015-16).
Since 2007, Shields leads all major-league pitchers in games started (308) and IP (2,055.1) and ranks among the leaders in quality starts (3rd, 31), opponents GIDP (3rd, 178), strikeouts (5th, 1,795), shutouts (T5th, 9), complete games (T6th, 21) and wins (8th, 123). He has recorded at least 10 victories, 200.0 IP and 160 strikeouts each season during that span. His streak of nine consecutive seasons with at least 200.0 IP is the longest active in the majors.
"We're pleased to add a starter of James Shields' caliber to our starting rotation. We believe this move makes the entire pitching staff stronger, and the club certainly benefits from his addition in terms of pitching depth and quality," said Rick Hahn, White Sox senior vice president/general manager. "He has proven to be one of the most dependable and durable pitchers in the major leagues over his career."
Shields, who was an American League All-Star with Tampa Bay in 2011, has made 11 career postseason starts, including three in the World Series. He owns a career record of 4-1 with a 3.00 ERA (24 ER/72.0 IP) in 11 career starts at U.S. Cellular Field.
Shields is signed through 2016 and holds a two-year player option for the 2017-18 seasons. If the player option is exercised, the club would hold an option for 2019.
A native of Newhall, Calif., he is the cousin of former White Sox outfielder Aaron Rowand. Shields originally was selected by Tampa Bay in the 16th round of the 2000 draft.
Johnson, 26, is 2-1 with a 2.94 ERA (16 ER/49.0 IP) and 35 strikeouts over eight starts with Class AAA Charlotte this season. He also is 0-2 with a 6.94 ERA (9 ER/11.2 IP) and 11 strikeouts in two starts with the White Sox in 2016.
Tatis Jr., 17, was signed by the White Sox as an international free agent on July 2, 2015. He is the son of former major-league third baseman Fernando Tatis Sr.