James Shields adds depth to already solid White Sox rotation

James Shields has thrown at least 200 innings in each of his last nine seasons. Denis Poroy/Getty Images

DETROIT -- The Chicago White Sox fortified an already formidable rotation by adding veteran experience and a veritable innings-eater in 34-year-old right-hander James Shields, who was acquired from the San Diego Padres in a trade announced on Saturday afternoon.

Why make the move?

The White Sox already have one of the strongest 1-2 starting pitching tandems in ace Chris Sale and Joe Quintana, but Shields will provide added depth to a rotation that ranks eighth in the league with an ERA of 3.61.

Since signing a four-year, $75 million deal with the Padres prior to last season, Shields has experienced a decline in performance, including an increase in home runs surrendered, a career-worst 2.11 strike-to-walk ratio and a changeup that has declined in efficiency, according to ESPN Stats & Information.

He does, however, come as advertised in terms of his ability to eat up innings. According to ESPN Stats & Info, Shields is the only pitcher to exceed 200 innings in each of his past nine seasons. Last season, his first with the Padres, he finished with 202 1/3 innings. Shields has also thrown 22 complete games, which is tied with the Detroit Tigers' Justin Verlander for the sixth-most thrown during the span in which he has been in the big leagues (2006).

What motivated the Sox to make such a move? For one, to remain competitive with the American League Central-leading Kansas City Royals, who are setting the pace within the division with a 30-24 record (the White Sox entered Saturday's game against the Detroit Tigers 2 1/2 games back). The fact that the White Sox bullpen has been such an area of angst lately has to further increase the value of adding a solid, experienced starter to the ranks.

The ability to trade for Shields while also convincing the Padres to retain a significant portion of his salary was likely integral to the deal as well, with San Diego reportedly eating more than $30 million on the remaining $58 million owed on a deal that runs through 2018 (though Shields has an opt-out clause after this year). And don’t forget that the White Sox already are saving $13 million from the unexpected retirement of Adam LaRoche, who walked away from the remaining year on his contract due to a dispute with the team over the time his son was allowed to spend in the team’s clubhouse.