James Shields is headed back to the American League. USATSI

The White Sox have completed a trade for Padres right-hander James Shields, the team announced Saturday afternoon.

Shields, 34, has pitched to a 4.28 ERA (90 ERA+) and 2.11 K/BB ratio after 11 starts. Across parts of 11 big-league seasons, Shields owns an ERA+ of 109.

In addition to Shields, the White Sox also get a reported $29 million in cash to offset a majority of the $56 million that Shields has left on his contract. As for the Padres, they receive right-hander Erik Johnson and infield prospect Fernando Tatis Jr.

On the Sox's side of things, they're angling for the AL Central title this season (as of Saturday morning, the SportsLine Projection Model gave the South Siders a 24.5 percent chance of winning the division and a 43.7 percent chance of making the postseason by any means), but they need some stability in the rotation behind ace Chris Sale and co-ace Jose Quintana. Mat Latos has regressed significantly after a hot start, and Carlos Rodon has struggled with his consistency. In the fifth spot, the White Sox have tried out three different pitchers, none of whom have thrived.

As for Shields, his numbers since going to the Padres prior to last season have been mediocre at best, which isn't surprising given his age. As well, he's making the jump back to the DH league and to a park that's a great environment for power hitters.

On that point, since the start of the 2015 season, Shields has given up 42 home runs in 269 2/3 innings. That's a not an ideal weakness to carry into an environment like U.S. Cellular Field. On the other hand, there's always something to be said for letting a brilliant pitching coach like Don Cooper try his hand with a pitcher who's shown greatness in the past. Let is also be noted that Shields is angling for his 10th straight season of at least 200 innings pitched.

As for the Padres' end, Johnson, 26, has a 4.50 ERA (89 ERA+) and 1.83 K/BB ratio across 18 career starts at the big-league level. Tatis, 17, is a 2015 signee out of the Dominican Republic and the son of former big leaguer Fernando Tatis.