Examining Brad Keller’s Success

Brad Keller is a 22-year old rookie for the Kansas City Royals, who they acquired from the Cincinnati Reds after they Rule 5 drafted him off Arizona last winter. He’s in the majors after a Double-A season that saw him post a 4.68 ERA, 1.52 WHIP, and 9% K-BB rate over 131 innings. He made the Hard-Throwing Relievers section of Eric Longenhagen’s KC prospects list. He spent the first two months of the season in that role, leaning on a 95 mph sinker to post a 2.01 ERA and 1.08 WHIP in 22 innings, but just a 7% K-BB rate.

Keller made his first start on May 30th and has added innings each start, culminating with Monday afternoon’s seven shutout innings against the Los Angeles Angels. It was his first time north of 100 pitches at 109 and also included a season-high six strikeouts. He had a 14:1 groundball-to-flyball rate and even netted 12 swinging strikes (tying his season-high). However, even with this start he still has just a 6% K-BB rate (how does it keeping going down?!) as a starter with a 2.45 ERA and 1.36 WHIP over 26 innings. How’s he doing it and can it continue?

He works with a three pitch mix, but it’s two fastballs (four-seamer, sinker) and a slider so I’m not super-enthused by such a limited arsenal. The one skill we’ve seen with regularity is the groundball rate. It’s up at 61% with all three pitches generating at least a 55% mark, but the strikeouts are awful and his walks, chase rate, first-pitch strike rate, and swinging strike rate are all below average. Gross. The heavy sinker is doing the bulk of the work for Keller, but I just can’t see this sustaining with these metrics.

Keller has shown a reverse platoon split as a starter with lefties at .436 OPS and a respectable 14% K-BB rate in 29 PA, but righties at .682 and 3% in 77 PA. He has that same 61% groundball rate against both sides, but the lefty BABIP is down at .222 while righties are .339. That heavy groundball lean has helped him keep the ball in the yard with just one homer allowed all season (and it came in relief back on April 20th), though a 3% HR/FB rate is certainly helping, too. I think it’s fair to expect HR suppression from Keller, but not necessarily at this incredibly elite clip.

Pairing his fastballs together, we see a .644 OPS which is 16th among 160 starters with at least 250 four-seamers and sinkers thrown, and the 61% groundball rate is sixth, but it comes with a 1% K-BB rate. One. Per. Cent.  By the way, I’ll point out that the four-seamer and sinker performances are relatively similar which is why I just combined the results. The slider has allowed a .577 OPS (59th of 107 starters w/99 thrown) with the same 61% groundball rate as the fastballs, which slots third behind only Clayton Kershaw (67%) and Zack Wheeler (62%). As you can see, Keller is consistent with that groundball rate and gets them off all three pitches.

That’s obviously his calling card. That’s the only way he remains at all successful here barring a sharp improvement in his strikeout and/or walk rates. At the end of the day, this feels like a right-handed Ty Blach and you should prepare accordingly. There have been 109 starters with at least 100 innings of a 10% or lower K-BB from 2015-17 and only 19 of those managed a sub-4.00 ERA. Of the 24 who were at 6% or lower, only Andrew Cashner’s super weird season last year netted a sub-4.00. Keller’s ERA is going up at least two runs.

Keller is an AL-only play and even that might be a bit dodgy with his upcoming schedule. He goes to Seattle, hosts Boston, and then heads out to the Southside of Chicago to face the White Sox for his next three starts heading into the All-Star break.