The Most Improved Pitchers Thus Far by Projected WAR

What follows represents an attempt by the author to utilize the projections available at the site to identify the five starting pitchers whose per-inning WAR projections have most improved since the beginning of the season.

For every pitcher, what I’ve done is first to calculate his preseason (PRE) WAR projection prorated to 150 innings, averaging together Steamer and ZiPS forecasts where both are available. What I’ve done next is to calculate the prorated WAR for every pitcher’s rest-of-season (ROS) WAR projection (again, using both Steamer and ZiPS when available). I’ve then found the difference in prorated WAR between the preseason and rest-of-season projection.

When I attempted a similar exercise two months ago, I used updated end-of-season projections instead of prorated rest-of-season ones. The advantage of the latter (and why I used it on last month’s edition of this post, as well) is that it provides the closest available thing to an estimate of any given player’s current true-talent level — which, reason dictates, is what one requires to best identify those players who have most improved.

Only those pitchers have been considered who (a) are currently on a major-league roster and (b) have recorded at least 20 innings at the major-league level and (c) are expected to work predominantly as a starter for the duration of the season. Note that Projection denotes a composite Steamer and ZiPS projection. PRE denotes the player’s preseason projection; ROS, the rest-of-season projection. Inning estimates for both PRE and ROS projections are taken from relevant pitcher’s depth-chart innings projection. Data is current as of Tuesday.

5. Tom Koehler, RHP, Miami (Profile)
Projection (PRE): 154 IP, 6.4 K/9, 4.1 BB/9, 1.0 HR/9, 4.56 FIP, -0.1 WAR
Projection (ROS): 81 IP, 6.7 K/9, 4.1 BB/9, 1.0 HR/9, 4.53 FIP, 0.1 WAR

Notes
Koehler’s per-inning projections haven’t improved so much that one would immediately assume he ranked among the league’s best pitchers by that measure. This is also the case with certain of the other players below. In such situations, said pitcher’s inclusion on the list is a result not merely of the raw improvements but (and probably moreso) the role in which that pitcher is expected to produce the relevant numbers. The preseason projections here at the site assumed Koehler would make about a third of his appearances in 2014 in relief. The current projections assume he’ll make all of his remaining appearances this season as a starter. In most cases, a pitcher deployed in a relief role will record superficially better per-inning numbers than those he would in a starting capacity — because he’s compared to other relievers for the purposes of calculating WAR, however, those superficially superior numbers aren’t actually superior for our purposes. In Koehler’s case, the per-inning projections haven’t changed much. That he’s expected to produce them in a starting capacity, however, is encouraging.

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4. Jesse Chavez, RHP, Oakland (Profile)
Projection (PRE): 131 IP, 7.0 K/9, 2.9 BB/9, 1.1 HR/9, 4.14 FIP, 0.3 WAR
Projection (ROS): 87 IP, 7.4 K/9, 2.8 BB/9, 1.0 HR/9, 3.91 FIP, 0.6 WAR

Notes
Chavez and Dallas Keuchel (below) are the two pitchers present here to have also appeared in the iteration of this same exercise that appeared last month. At that point, his combined Steamer and ZiPS projection called for hom to produce strikeout and walk rates of 7.7 and 2.8 per nine innings, respectively, plus a 1.0 HR/9 — good, that, for a 3.93 FIP. What he’s actually produced in the meantime is the following (over six starts and 36.1 innings): 6.2 K/9, 2.5 BB/9, 0.5 HR/9, 3.42 FIP. So: fewer strikeouts, fewer walks, half the home runs, and a lower FIP. Competent enough, however, to allow him to remain one of the league’s most improved pitchers.

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3. Chase Whitley, RHP, New York AL (Profile)
Projection (PRE): 1 IP, 6.7 K/9, 3.7 BB/9, 1.3 HR/9, 4.78 FIP, 0.0 WAR
Projection (ROS): 52 IP, 6.6 K/9, 3.3 BB/9, 1.3 HR/9, 4.71 FIP, 0.0 WAR

Notes
Like Koehler above, Whitley’s anticipated role has changed since the beginning of the season. Unlike Koehler, however — who was projected to record 25 starts — Whitley wasn’t so obviously expected to log considerable (or any) innings at the major-league level. He has done, though, to good effect — his Monday start at Toronto notwithstanding. Projected originally by Steamer to record a walk rate of 3.7 per nine, the 25-year-old right-hander has more than halved that mark (1.5 BB/9) over eight starts and 42.0 innings. That performance has dropped his projected walk rate by about 0.4 per nine — a mark made more impressive, again, by the change in role.

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2. Dallas Keuchel, LHP, Houston (Profile)
Projection (PRE): 68 IP, 6.0 K/9, 3.0 BB/9, 1.0 HR/9, 4.23 FIP, 0.4 WAR
Projection (ROS): 91 IP, 6.5 K/9, 2.8 BB/9, 0.8 HR/9, 3.87 FIP, 1.0 WAR

Notes
As with Jesse Chavez above, Keuchel appears once again on this list of most improved pitchers. As with Chavez, there’s likely some pleasure and/or insight to be gained from inspecting his rest-of-season projection from a month ago and then the actual, real numbers that he’s produced in the six starts and 42.0 innings since then.

Here’s a table which includes that kind of data. (Note: Proj denotes his rest-of-season projection as of May 20th, while Real represents his actual production.)

Type	K/9	BB/9	HR/9	FIP
Proj	6.5	2.8	0.9	3.93
Real	6.0	3.0	0.2	3.20

Keuchel has recorded slightly fewer strikeouts and slightly more walks than expected — which, that’s not a fantastic development. What else he’s done, however, is also to concede just a single home run — on June 11th against Aaron Hill — over those same 42 innings. Probably as a result of that, his expected home-run rate has dropped slightly since this same exercise last month.

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1. Chase Anderson, RHP, Arizona (Profile)
Projection (PRE): 1 IP, 6.3 K/9, 3.2 BB/9, 1.2 HR/9, 4.60 FIP, 0.0 WAR
Projection (ROS): 88 IP, 6.9 K/9, 3.0 BB/9, 1.2 HR/9, 4.48 FIP, 0.2 WAR

Notes
The 26-year-old Anderson would have appeared on this list last month were it not for having recorded fewer than 20 innings (i.e. the nearly arbitrary threshold imposed by the author) at that point. Now he’s eligible, however, and receives the temporary distinction of baseball’s most improved pitcher. As with Chase Whitley above, it wasn’t entirely obvious that Anderson would record a major-league inning this year, let alone a number of them. What he’s done, though, is to produced the second-highest WAR among Arizona pitchers over the last month. As is the case with some of the pitchers above, the effect of Anderson’s improvement is obscured by his raw per-inning stats — owing, that is, to how the preseason projections represent innings thrown as a reliever, while the current rest-of-season ones apply to a starting role.

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Three additional notes:

• Sixth among pitchers by the measure used here is Washington right-hander Tanner Roark (+1.1 WAR per 150 IP). Calculating any of the pitchers after him would require a sort of due diligence, however, which the author is unwilling to perform.
• Roark’s teammate Blake Treinen would actually appear atop this list had he not been demoted two week ago to Triple-A. Treinen has recorded a 59.8% ground-ball rate over 30 innings for the Nationals and conceded precisely zero home runs at the minor- or major-league level this season.
• Despite having allowed all those different runs, Randy Wolf fares well by this measure, too. He was recently waivers by Miami and, even more recently, signed by Baltimore.