Commentary

Work factor impact on starters

Which ace pitchers could be due for a late decline based on extra stress?

Updated: July 26, 2011, 12:50 PM ET
By AJ Mass | ESPN.com

Greetings, dear readers! Your usual tour guide, Tristan H. Cockcroft, is getting a well-earned recharge of the batteries this week, and he asked me to take over on the microphone to point out the top attractions as this double-decker bus heads down Starting Pitcher Boulevard.

60 Feet 6 Inches

Last week's "60 Feet, 60 Inches" focused on the dreaded "innings cap" and how it might impact some of the younger pitchers in the league down the stretch. My colleague stated the opinion that "there is far too much emphasis on innings pitched, which shouldn't be the only measure of a pitcher's workload, as things such as total pitches, stressful pitches … should also be taken into account." I couldn't agree more.

It may be hard for some to remember a time when pitch counts weren't all the rage in baseball, but back in ye olde days, pitchers were actually expected to finish every game they started. I know, right? Today, once a pitcher reaches that "magic" 100th pitch, the manager is already halfway to the mound to make a change, but back in 1989, Nolan Ryan threw 130 or more pitches 16 times. Today, Bartolo Colon and Livan Hernandez are the only active pitchers to have surpassed that milestone even three times in a single season.

The key to identifying which pitchers might be headed toward end-of-the-year slumps due to overwork -- and therefore which pitchers to start shopping now while the going is still somewhat good -- is not, however, simply counting pitches, but rather taking a look at who is throwing more pitches than they should. If we can find the pitchers who are under constant stress by working too hard inning after inning, start after start, it will be far more predictive of a late-season decline than a simple pitch count could ever be.

To that end, I've spun off from the work of Tom Tango, who has done a lot of work with estimated pitch counts, and especially into figuring out the expected number of pitches a pitcher "should have thrown," based on their innings pitched, strikeouts, walks and hits allowed. It stands to reason that if we have a solid formula for predicting the expected number of pitches based on actual game outcomes, which Tango's work does provide us, then any variance between that number and the actual pitch count is likely the result of a pitcher working harder than he needs to.

With that in mind, let's take a look at what I like to call work factor: the difference in the expected number of pitches and the actual number of pitches thrown.

Cruise Control

Here are eight arms that work factor indicates have put less stress on their arms this season than what is historically expected of pitchers who have faced the same numbers of batters with the same statistical results. Additionally, all of them have an overall P/IP (pitches per inning pitched) under 15.0, which typically signals an even workload throughout the season, and less of a likelihood of the development of "tired arm syndrome" as the end of the season approaches. (Stats through Sunday's games.)

What is interesting to note in this group is that over the past five seasons, only Jeff Karstens (2008) had even one season in which he threw more pitches than the expected total, so there's a track record here of being somewhat more efficient, even as the innings add up. CC Sabathia may well be on pace for 250 innings, his highest total since 2008, but the stress on his arm is at its lowest level since he became a 200-plus-innings workhorse. Tim Hudson, who many feared might be overtaxed after throwing more innings in 2010 than the previous two injury-filled campaigns combined, is actually showing no signs of slowing down as he passes his 36th birthday.

Working Overtime

Conversely, if you're looking for reasons to worry, here are eight arms that work factor indicates have faced far too many deep counts and may well run out of gas sooner rather than later. Additionally, all of them have a P/IP over 15.5, some dramatically so, which typically signals a pitcher who may work harder than his peers in order to get through the same number of opposing hitters.

Dan Haren, who has a reputation for second-half disappointment, usually keeps his actual pitch count close to the expected value, but this season he's clearly had to exert more effort than usual in order to keep his ERA down to 3.10. His high pitch count is all the more alarming considering how few walks he's issued. In fact, Monday night's 123-pitch no-decision against the Cleveland Indians, not included in the chart above, added another 16 pitches to the work factor tally -- the clock is ticking.

Red flags also abound for Yovani Gallardo, not so much for the multiple disastrous outings, but more so for the fact he's needed to throw 110 pitches or more in his quality starts. Then there's Alexi Ogando. Even without factoring in the reality of his overall innings pitched being monitored, it's clear to me that there's probably not a lot left in his tank for 2011 anyway.

Certainly, you don't want to use work factor as the only reason to consider getting out from under these anchors before it's too late. But if you're already seeing smoke, throwing another stick on the pile isn't going to make things any better.

What's Up, Doc?

Finally, a note on Roy Halladay, who traditionally has been the poster child for work factor. Since 2007, Halladay has thrown 40 complete games, well more than any other active pitcher, with only Cliff Lee and Sabathia having more than 14 over that time. Yet over that same time, he has always exhibited the ability to get through lineups using as few pitches as possible.

It is interesting, though, that 2011 has been a bit of a change for Halladay. Through Sunday's games, he has managed to shave only five total pitches off his expected pitch count. His totals for the previous four seasons: 165, 249, 118 and 139.

While we're not saying that time has finally caught up with the 14-year veteran, and he still ranks as our No. 1 pitcher for the rest of the season, when he's suddenly leaving games early due to heat exhaustion, let's just says we're keeping our eye on him a lot more closely than in seasons past.

Three Up

Vance Worley, Philadelphia Phillies: Because he's been primarily a ground-ball pitcher (44.4 percent of all balls put into play), he's been able to excel at Citizens Bank Park to the tune of a .168 BAA and a 1.50 ERA. Even if he's moved at the trade deadline to a potentially less formidable lineup, that's a skill that translates to any environment. So as long as he keeps the ball down, things are looking up.

Josh Collmenter, Arizona Diamondbacks: The concern with Collmenter was that his success was based on his unusual delivery and that once he started facing teams who had already been fooled once -- well, we all know how that Who song ends. Yet with two quality starts in a row, featuring 11 strikeouts and zero walks, both against repeat customers, perhaps it is time to give this young pitcher his just due.

Brandon McCarthy, Oakland Athletics: Since returning from a right shoulder injury on July 4, McCarthy has certainly struggled in terms of endurance, lasting into the seventh inning just once. Yet, he's keeping the bases relatively clear (.292 OBP) and if he gets just a little bit luckier on the defensive end to increase his 61.9 LOB percentage and bring it a little bit closer to the league average (72.6) then his ERA is due for a huge drop.

Three down

Brett Myers, Houston Astros: Whatever goodwill Myers built up in June, when he had a .201 BAA, evaporated into the mists of summer as July brought with it a .309 BAA, along with a 5.40 ERA and 0-3 record to boot. With the Astros most likely going to be selling off the serviceable parts of their lineup, we're not sure it gets better for a guy unlikely to get too many offers himself.

Jhoulys Chacin, Colorado Rockies: At what point do you start to believe the winless July and 8.18 second-half ERA and discount the 2.71 ERA he had back on June 21? For me, it's now, after watching Chacin give up seven home runs in his last five starts, while seeing his K/9 rate drop to 7.1 from 8.0 over that same time while his BAA has risen 74 points. Opposing hitters have simply caught up to the Rockies pitcher.

Jake Arrieta, Baltimore Orioles: It's not only the 7.17 ERA over his past four starts, or the .326 batting average against, or the fact he's given up seven home runs while striking out only twice as many hitters -- though of course, all those are pretty valid reasons to downgrade Arrieta. Throw in a work factor of 51, and 17.3 P/IP and the sky is definitely falling here.

AJ Mass is a fantasy baseball, football and college basketball analyst for ESPN.com. His book, "How Fantasy Sports Explains the World" will be released in August. You can email him here.

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