Royals: Should Kansas City bring back Jake Diekman?

The Kansas City Royals signed a veteran left-handed free agent to bolster their bullpen in 2019, then traded him in a midsummer deadline deal. Should the club reunite with him for 2020?

The Kansas City Royals, spoiled by the unstoppable bullpens that fueled their runs to two straight World Series in 2014 and 2015, but hampered since by inconsistent and ineffective relievers, signed veteran Jake Diekman as a free agent before the 2019 season. The club then traded him close to the July trade deadline; faced again with a subpar relief corps, should the Royals sign him this winter and bring him back?

The Royals believed Diekman could fill their need for a reliable left-handed reliever when they signed him a month before Spring Training last season. A seven-season major league veteran, he arrived relatively well-credentialed: he owned a double-digit SO9, with a high of 12.7 with Philadelphia in 2014, averaged over 52 appearances per season, and consistently bested the average ERA+.

Diekman’s primary flaw coming into 2019 was control. Before his Royals’ debut, he posted a BB9 over 4.5 five times, including 5.9 (24 walks in 36.2 innings) with the Phillies in 2015, 5.2 (a combined 31 in 53.1 innings) with Texas and Arizona in 2018, and a small sample size  8.4 (10 in 10.2 innings) with Texas in 2017.

Kansas City was clearly taking a chance on Diekman. Traded to Arizona by the Rangers at the 2018 July trade deadline, he made 24 appearances for the Diamondbacks, gave up 15 runs (12 earned) in 14.1 innings for an ugly 7.53 ERA and even uglier 9.42 RA9. He walked eight in those 14.1 innings, although he maintained his impressive strikeout rate with 18.

What Diekman brought to Kansas City, then, was a left-handed bullpen arm, the ability to pitch often, and an enviable strikeout record.

But his season in KC was a curious mix. Frequently used by manager Ned Yost before the deadline trade to the A’s, Diekman appeared in 48 games, pitched 41.2 innings, and predictably struck out more than a batter an inning — 63, to be exact, for a flashy 13.6 SO9. Just as predictably, though, he suffered control problems: he hit eight batters, threw four wild pitches, and posted a 5.0 BB9. And he went 0-6; although he surrendered the winning run in three of those losses, others surrendered the go-ahead runs in the other three.

His control didn’t improve with the A’s. In 20.1 innings, Diekman hit three batters, threw two wild pitches, and walked 16 (7.1 BB9). Oakland declined Diekman’s $5.75 million mutual option and bought him out for $500,000.  

Now, Diekman is back on the market, and left-handed relievers are, as always, in short supply. Of the four regular southpaw relievers on the Royals’ 40-man roster — Tim Hill, Richard Lovelady, Randy Rosario and Gabe Speier — only Hill and Rosario have any significant major league experience. Could Diekman help the club? Perhaps.

Although Diekman received a look as a starter in the Phillies’ system, he’s never started a major league game and his nine career saves prove he’s not a closer; his control issues make him an ill fit for a set-up role. Diekman’s value lies in his ability to pitch frequently and to strike out hitters at a formidable rate, making him an adequate candidate for a middle/late-inning relief role in the Royals’ muddled bullpen.

KC has another reason to consider Diekman. Beginning in 2020, relievers must face at least three batters unless they first retire the side, suffer injury or fall ill. Managers who favor traditional righty-righty/lefty-lefty matchups (new KC skipper Mike Matheny?) can’t bring in a lefty to face a lefty, then replace him after one batter with a righty to face a righty. Diekman, a southpaw, fares comparatively well against lefties and righties alike.

In 2019, for example, 105 left-handed hitters hit .224 against Diekman while 177 right-handers (that convention suggests will perform better than lefties against left-handed pitchers) hit .210; although he walked more left-handers, he struck out more right-handers. Over Diekman’s career, lefties have slashed .234/.335/.306, righties, .221/.334/345. Using Diekman under the three batter rule shouldn’t be foreboding.

Diekman also liked his time with the Royals, so a return to Kansas City could suit him. And his price could be right, as his 2019 base salary was $2.25 million and Oakland’s rejection of his $5.75 million option means his ceiling won’t be high.

Jake Diekman is a serviceable, if unspectacular, left-handed reliever with a superb strikeout rate and durability. A return to Kauffman Stadium makes some sense: KC is itself an unspectacular team a season or two from contending, the Royals need a reliever for lower-leverage middle and long relief assignments, he could serve as a veteran mentor to KC’s stable of young hurlers, he would be a likely trade chip in July, and Diekman likes Kansas City. If the price is right, the Kansas City Royals should at least consider a reunion with Diekman.