RELIEVERS: pxERA and xERA as early filters

This week, the column looks at Expected ERA (xERA) and projected Expected ERA (pxERA) as indicators for success by relievers. xERA and pxERA have long been a staple at BaseballHQ.com and have proven again and again to be successful in figuring out which skill sets are the best ones—even while newer, seemingly sexier metrics have come into vogue. While we are only in the fourth week of the season, we can use these indicators to get a sense of who is expected to have top skills, who is exhibiting top skills and how you can separate wheat from chaff using filters and lists with xERA and pxERA as a guide.

Let us start with the top skill sets by pxERA—that is—the projected best expected ERAs (pxERA under 3.10). As you might imagine, there are a lot of closers on this list, so let's start with them:

                    IP  ERA xERA pxERA WHIP  Dom  Cmd HR/9   G/F   BPV
================   === ==== ==== ===== ==== ==== ==== ==== ======= ===
A.Miller (NYY) (L) 8.0 0.00 0.95  1.91 0.38 16.9  --   --   55/36  337
Britton (BAL) (L)  7.0 1.29 1.81  2.24 0.71 11.6  4.5  1.3  64/14  181
K.Jansen (LA)      8.7 0.00 2.16  2.25 0.35  9.3  --   --   50/35  196
Kimbrel (BOS)      8.0 3.38 3.02  2.44 1.00 15.8  2.8  1.1  23/69  133
Robertson (CHW)    7.3 1.23 2.56  2.46 0.68  9.8  4.0  --   50/31  138
H.Rondon (CHC)     4.0 0.00 1.13  2.67 0.25 18.0  --   --   40/60  342
Melancon (PIT)     7.7 1.17 2.86  2.71 0.91  7.0  --   --   45/27  150
Familia (NYM)      8.0 2.25 4.07  2.86 1.75  7.9  1.8  --   63/22   61
Rosenthal (STL)    6.0 3.00 0.72  2.90 1.00 21.0  4.7  1.5  75/13  310
Gregerson (HOU)    6.0 1.50 2.84  2.93 0.67  6.0  2.0  --   67/13   72
Madson (OAK)       9.7 1.86 3.09  3.02 0.83  7.4  8.0  --   41/30  128
W.Davis (KC)       7.7 0.00 3.78  3.03 0.78  9.4  1.6  --   43/57   32
Ziegler (ARI)      9.0 1.00 3.31  3.09 1.67  8.0  2.0  --   67/15   81
Jeffress (MIL)     7.7 3.52 3.32  3.09 1.17  5.9  5.0  1.2  55/27  107

It has been a pretty good April for most of these closers. Many of them have actual ERAs even lower than their xERA and pxERA. The only two that do not are Craig Kimbrel (RHP, BOS) and Jeremy Jeffress (RHP, MIL). In the case of Kimbrel, the 69% flyball rate is uncharacteristic but otherwise, he is not very far away from the projection. In the case of Jeffress, the 5.9 Dom is quite low and needs to be monitored. Remember, too, that this is only 5-8 innings of actual data.

When we look at the skills exhibited so far (using xERA over 3.10), the outlier skill sets so far are Jeurys Familia (RHP, NYM), Wade Davis (RHP, KC), Brad Ziegler (RHP, ARI) and Jeffress—so only four of these closers. Familia has a high WHIP and xERA, presumably because of walks (1.8 Cmd). Davis has a smoke-and-mirrors 0.00 actual ERA and a solid 0.78 WHIP, but the 1.6 Cmd ratio is uncharacteristic and should be monitored. Ziegler has a high WHIP, but his skill set is otherwise in line with his usual extreme groundball output and if anything, he has a higher Dom than usual.

It is certainly worthwhile to monitor these early nitpicks, but this group is generally the list of your elite closers and should be able to maintain excellence all season long, as projected by pxERA.

Here are the non-closers with pxERA under 3.10:

                    IP  ERA xERA pxERA WHIP  Dom  Cmd HR/9   G/F   BPV
================   === ==== ==== ===== ==== ==== ==== ==== ======= ===
Betances (NYY)     9.0 0.00 0.84  2.36 0.78 22.0 11.0  --   36/27  356
Cecil (TOR) (L)    8.0 3.38 3.78  2.68 1.38  9.0  4.0  1.1  33/38  112
Strop (CHC)        7.3 1.23 1.02  2.68 0.41 11.0  9.0  --   93/7   237
Givens (BAL)       9.0 3.00 2.44  2.79 1.56 16.0  4.0  1.0  37/37  195
Dyson (TEX)        9.0 3.00 2.99  2.91 1.33  8.0  2.0  1.0  68/18   82
N.Jones (CHW)      8.7 1.04 2.79  2.91 0.35  8.3  8.0  --   38/38  138
O'Day (BAL)        7.3 0.00 2.43  2.94 1.09 14.7  4.0  --   33/33  177
Grimm (CHC)        6.0 3.00 2.24  2.99 0.67 10.5  --   1.5  47/33  214
Giles (HOU)        7.7 7.04 3.27  3.04 1.57 12.9  5.5  3.5  29/33  176

Brett Cecil (LHP, TOR) has a higher than expected actual ERA and xERA to date, presumably due to a pedestrian 1.38 WHIP coupled with the 1.1 HR/9. This will correct itself. Ken Giles (RHP, HOU) may be in set-up for the Astros, but his BPV is far greater than Luke Gregerson (RHP, HOU) despite the outwardly terrible 7.04 actual ERA. Giles is also a victim of a poor WHIP and gopheritis, but the current 12.9 Dom, 5.5 Cmd ratio and history of excellence would leave the projection intact—for now. The rest of these elite relievers are meeting or exceeding the elite expectations projected by pxERA. Perhaps most notable in this grouping is Sam Dyson (RHP, TEX) who has a closer who is not on the elite list and fellow elite set-up man Keone Kela (RHP, TEX) on the shelf for the foreseeable future. This combined with the elite skill set makes Dyson a superb non-closer to own.

Now let's flip this around. Here are the closers who have an expected ERA (xERA) under 3.10 after three weeks, starting with closers:

                    IP  ERA xERA pxERA WHIP  Dom  Cmd HR/9   G/F   BPV
================   === ==== ==== ===== ==== ==== ==== ==== ======= ===
Rodney (SD)        6.3 0.00 2.32  3.52 0.95  9.9  7.0  --   53/27  172
A.Colome (TAM)     7.3 1.23 2.91  3.67 0.95  9.8  4.0  --   44/33  132
Cishek (SEA)       9.0 1.00 2.95  3.52 0.56  9.0  9.0  1.0  41/50  154
Vizcaino (ATL)     6.0 0.00 3.05  3.45 1.50 13.5  1.8  --   71/21   90

Fernando Rodney (RHP, SD) is having a fantastic April, with a 0.00 actual ERA fully supported by a 2.32 xERA and 0.95 WHIP, 9.9 Dom, 7.0 Cmd ratio, no home runs, a nice 53/27 G/F ratio and 172 BPV. Not what anyone might have predicted. The 3.52 pxERA is not so terrible that this saves vampire might just hang in there for the foreseeable future. But, the skill set eroded terribly in 2015 and cannot be counted on long term, even in San Diego. Ride him while he is hot.

Steve Cishek (RHP, SEA) is another surprise visitor on this list, with a 1.00 actual ERA, supported by a 2.95 xERA, 0.56 WHIP and solid skill BPIs across the board. Cishek was superb before 2015, then was lousy for the Marlins, lost his job, was nothing special for the Cardinals in set-up and was not expected to be a strong skill set in 2016. Yet here he is. If Cishek has rediscovered what he had in 2014, then he could close for Seattle all season. A skill set to monitor for hiccups.

Alex Colome (RHP, TAM) is filling in nicely for Brad Boxberger (RHP, TAM) and gives the Rays the luxury of bringing Boxberger back slowly. Like Rodney and Cishek, Colome has a strong 1.23 actual ERA and 0.95 WHIP that is fully supported by the skills BPIs. How long he remains the closer depends on when Boxberger returns, how well Boxberger pitches when he returns, and how well Colome can hold onto these elite results. But the skills are excited so far in April.

Arodys Vizcaino (RHP, ATL) has certainly outpitched Jason Grilli (RHP, ATL) to get named the "primary closer." One worry with Vizcaino's skill set to date is the high WHIP due to walks—the juxtaposition of a whopping 13.5 Dom and 1.8 Cmd ratio means that Vizcaino is walking 7.5 batters per nine innings—not good. The large groundball rate helps considerably. It remains to be seen whether Vizcaino can correct the walk rate or whether he will succumb to it. So far, though, the 0.00 actual ERA is prevailing.

And here are the non-closers with xERA under 3.10 so far in 2016:

                    IP  ERA xERA pxERA WHIP  Dom  Cmd HR/9   G/F   BPV
================   === ==== ==== ===== ==== ==== ==== ==== ======= ===
J.Wilson (DET) (L) 7.3 0.00 1.23  3.27 0.95 13.5 11.0  --   67/7   255
Otero (CLE)        4.0 0.00 1.74  4.11 0.25  9.0  --   --   67/22  207
H.Neris (PHI)     10.3 0.00 1.78  4.05 0.68 14.8  5.7  --   47/35  221
N.Feliz (PIT)      8.3 2.16 1.82  4.03 0.36 11.9  --   1.1  44/44  236
Bastardo (NYM) (L) 9.3 2.89 1.83  3.42 1.07 14.5  7.5  1.0  48/19  234
Vincent (SEA)      6.7 2.70 2.00  3.39 0.60 10.8  --   2.7  56/31  228
P.Klein (TEX)      5.3 0.00 2.03  4.29 0.38 11.8  --   --   36/45  227
W.Harris (HOU)     8.7 1.04 2.08  3.11 0.69  9.3  9.0  --   78/22  196
P.Baez (LA)        7.3 2.45 2.15  3.22 0.82 13.5  5.5  2.5  47/33  202
Siegrist (STL) (L) 6.7 0.00 2.17  3.41 0.45 13.5 10.0  --   33/58  218
J.Chavez (TOR)     6.0 1.50 2.17  3.60 1.17 13.5  9.0  1.5  36/29  216
Diekman (TEX) (L)  5.3 0.00 2.24  3.30 0.38 10.1  6.0  1.7  67/33  182
S.Kelley (WAS)     5.3 0.00 2.41  3.14 1.12 13.5  8.0  --   46/38  221
Abad (MIN) (L)     6.7 0.00 2.42  3.70 0.60  9.4  3.5  --   50/21  125
Neshek (HOU)       6.3 2.84 2.42  3.73 0.63 11.4  8.0  2.8  29/36  173
O.Perez (WAS) (L)  4.3 2.08 2.42  3.57 1.15 16.6  2.0  --   67/33  120
S.Oh (STL)         9.7 1.86 2.46  3.60 0.93 14.9  2.7  --   50/43  145
Rivero (WAS) (L)   8.7 2.08 2.48  3.50 0.69  8.3  8.0  1.0  59/27  158
Axford (OAK)      10.0 0.00 2.55  3.47 0.80  4.5  --   --   77/17  136
K.Herrera (KC)     9.3 0.00 2.55  3.34 0.86 12.5  6.5  --   38/43  190
A.Reed (NYM)       9.0 3.00 2.68  3.50 1.00 11.0  5.5  1.0  52/30  174
Hembree (BOS)      4.7 0.00 2.68  3.95 0.64 13.5  7.0  --    0/67  169
D.Hudson (ARI)     8.7 1.04 2.75  3.44 0.35  7.3  7.0  --   43/33  124
D.Phelps (MIA)    11.0 1.64 2.83  4.14 0.64 10.6  4.3  --   41/50  144
R.Dull (OAK)       9.0 3.00 2.83  3.35 0.33  9.0  9.0  1.0  37/58  150
C.Devenski (HOU)  10.3 0.87 2.88  3.84 0.87  8.7 10.0  0.9  28/44  139
Brach (BAL)       11.3 0.79 2.92  3.57 0.71 10.3  3.2  --   42/42  120
Hochevar (KC)      7.7 2.35 2.92  3.75 0.78 11.7 10.0  1.2  33/61  191
T.May (MIN)        9.0 2.00 2.94  3.60 1.33 15.0  2.5  1.0  44/39  130
A.Wilson (DET)     4.0 0.00 3.09  4.11 0.50  9.0  --   --   10/60  150

This list is only actionable if you really believe in the three weeks and not the projections, which is a higher risk view. There are relievers on this list who will not have a robust projection, though. Take Seung Hwan Oh (RHP, STL). His projection is based on the MLE from his prior league. Similarly, Trevor May (RHP, MIN) has a projected built on a mix of starting and relief statistics. The change in role for David Phelps (RHP, MIA) to a one-inning reliever could be helping him. Before rostering these non-closers, think about the role they have and the chance or lack of chance they have to move up and get into the saves mix. Also think about what the pxERA says about them. There is a difference between Phil Klein's (RHP, TEX) 4.29 pxERA and Will Harris's (RHP, HOU) 3.11 pxERA. But for now, these relievers are hot.

Next week, this column looks at relievers who had the best April.


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  For more information about the terms used in this article, see our Glossary Primer.