Robertson has been nasty, but how long does he stay?

Though the White Sox are in the midst of rebuild and don’t look to be contenders this season, it’s been quite a busy start to the season and all eyes have been on the South Side.

Part of the reason is that the White Sox still possess players that are considered valuable trade assets and, though it feels as if the first pitch of the regular season was thrown just yesterday, it’s getting closer to the time for folks to start trade deadline rumors. Other major league teams are settling in, baseball is figuring out contenders that need a boost, and who is in the position to sell.

Though Jose Quintana has gotten off to a less-than-admirable start, no one is truly concerned about him. There is still plenty of time for him to pick it up before the trade deadline at the end of July, if in fact the White Sox are looking to deal him at all this summer.

But, as all eyes have been focused on Quintana, many have let the success David Robertson’s success pass by. Robertson has been absolutely spectacular this season, quickly giving his value on the trade market a boost.

Robertson, now 32 years-old and on his 10th season in the majors, has thrown 21.1 innings this season—on pace for his usual 60 plus innings—to the tune of a 3.38 ERA. Doesn’t sound all that fantastic but, of course, there is more than meets the eye. Robertson currently owns a 2.68 FIP and, for the moment, a career low 1.74 DRA. These statistics are more telling of a pitcher’s true performance; they are independent of what the defense behind him does and, therefore, a better measure of the individual player’s true talent level.

Robertson’s 12.39 K/9 is his best in a White Sox uniform and best since his final season with the Yankees in 2014. Though Robertson owned a 1.85 BB/9 during his first season on the South Side, looking at his BB/9 over the course of his career quickly shows you that his 2015 season was an outlier in terms of walks. Robertson is currently walking just 3.1 batters per nine, while the AL average is currently sitting at 3.43. Not bad for a 32 year-old closer on a relatively inexpensive contract.

One concern for Robertson is the drastic decrease he’s seen in his groundball rate. Robertson’s pitching repertoire hasn’t seen a drastic change and still consists of his signature Mariano Rivera-taught cutter, a curveball with exceptional breaking action, as well as a sinker, and a changeup. However, Robertson has seen his groundball percentage dip from 45 percent in 2016, to just 35 percent in 2017. The concern there is that Robertson has seen a significant uptick in his fly ball rate. Robertson’s fly ball rate is now 51 percent, up from 40 percent in 2016, and by far a career high. This hasn’t been an issue for Robertson, who has only allowed 2 home runs and has seen his HR/FB% drop by .6 percentage points to 9.1. However, depending on which teams are scouting him, this could be a red flag on the radar for the closer. However, Guaranteed Rate Field is known as a notoriously hitter friendly park — so if Robertson were to struggle with giving up fly balls for home runs anywhere, it would likely already be happening in Chicago.

Robertson is currently on the third year of a four-year deal that will pay him just $12 million in 2017 and $13 million in 2018. Considering how baseball saw the closer market skyrocket this offseason, and Robertson is considered to be in nearly the same talent pool as the three closers who received hefty deals, Robertson has dual trade value. What teams are willing to give up for a closer with the success Robertson is seeing as well as the contract that he comes with will be something the White Sox should leverage during this season’s trade deadline.