PECOTA Day 2.0: Rest-of-Season Movers and Shakers

Most seasons, it seems, the Giants are a tough team to read, a tough team to cover, a tough team to talk about. They're three-time champions in the last five years, but there has yet to be any season in which it felt like they were some infallible juggernaut. To the contrary, they seem to be forever cobbling together a winner, often on the strength of some unexpected boost from a theretofore unknown entity. Last season, especially late in the season, that player was Joe Panik. This year, though the Giants don't look like a playoff team at the moment, they've gotten a similar (and similarly surprising) jolt from Matt Duffy.

Panik and Duffy don't have a great deal in common. The former was the team's first round pick in 2011; Duffy was an 18th rounder in 2012. Duffy moved through the minors considerably more quickly, earning a mid-season promotion from the South Atlantic to the California League in 2013. Panik got a full season in the Cal League, and then a full season with Double-A Richmond. It wasn't until he mashed Triple-A pitching in 2014 that he earned a mid-season bump, but that bump saw him move into an important role on the eventual World Series winner. Duffy put up better numbers than Panik for the majority of his minor league career, but never saw Triple-A, and graduated (permanently, it appears) to The Show after more than 500 fewer plate appearances than Panik had.

What's interesting about Panik and Duffy is that, a half-season on, they appear to be important parts of the Giants' offense, helping paper over the injury problems that have plagued the team, not to mention the free-agent departures of Pablo Sandoval and Michael Morse. Here are their stats to date:

Through July 12, 2015

Compare that to what PECOTA projected them to deliver before the season:

Preseason PECOTA Projections, 2015

You start to see what I mean about unexpected boosts and surprising sources. Since we're talking about PECOTA's view of the second half today, let's see whether Duffy and Panik's performances have been enough to change a projection system's tune.

Rest-of-Season PECOTA Projections, 2015

It certainly helps that Duffy and Panik have limited MLB track records; PECOTA is more willing to change its view of players without well-established levels of performance against big-league competition. It's nice, though, to know that there are players who can at least move the needle by defying our expectations over half a season. If the numbers moved much further toward the two players' first-half performances, we'd probably raise an eyebrow. If they moved much less, we'd know we were dealing with a system too entrenched in track records, rooted to the ground and unable to move when the truth runs a few strides ahead.

In celebration of the system's sensitivity to new data, and because it's important to know where we most need to adjust what we expected when the season began, here are a handful of other players who have changed PECOTA's mind (to some extent) over the course of the first half.

Bryce Harper
Shocking, I know. Harper's corner-turn has proven totally real, and while PECOTA isn't ready to trust him to put up a Peak Barry Bonds season, it's changed its outlook on him significantly.

Preseason and Rest-of-Season PECOTA Projections, 2015

Ian Desmond (.265 to .259) and Ryan Zimmerman (.291 to .283) have had rough first halves, and PECOTA has lowered its expectations accordingly. The Nationals had a .552 expected winning percentage before the season began, but their rest-of-season expectation is .546. It's a small difference, but it's the difference between 89 and 88 wins. If they're going to cruise to the NL East title the way most people expected them to this spring, they'll need Harper to keep mashing.

Steven Souza Jr.
Before the season, PECOTA boldly pegged Souza for an All-Star-caliber rookie season. Despite his uneven professional track record, the system looked at his combination of power, patience, and speed and decided Souza would flash it all in his first prolonged encounter with big-league pitchers.

It hasn't gone as smoothly as Souza might have hoped. He's striking out 35 percent of the time and his power and BABIP skills haven't been able to outrun those problems entirely. PECOTA's not giving up on him, but it's beginning to back off.

Preseason and Rest-of-Season PECOTA Projections, 2015

Only four teams are scoring fewer runs per game than the Rays, but the team is 46–45. It's helped that they've gotten unexpectedly good production from Joey Butler, Logan Forsythe, and Brandon Guyer, but they need more from Souza if they want to reclaim the lead in the AL East.

Jacob deGrom
Do your very best not to overreact to deGrom's remarkable All-Star performance. It was very cool, but probably nothing a dozen or so other pitchers couldn't do every five frames or so if they were shifted into single-inning relief. Carl Hubbell it was not.

That said, deGrom has done enough now to prove to PECOTA that he's more than the somewhat unimpressive mid-rotation arm he appeared to be during his minor league career. His second-half projection is significantly rosier than his preseason one.

Preseason and Rest-of-Season PECOTA Projections, 2015

The Mets are in a strange limbo, trailing and clearly inferior to the Cubs and the Nationals, not really in a playoff position, but too good to give up on the season. A strong second half from deGrom is vital to any hopes they have of getting back into the postseason.

Mike Zunino
It's not like PECOTA was in love with Zunino before the season began. It just saw a little glimmer of the upside he showed before the Mariners rushed him to Seattle, most of that coming from his considerable pop. He's still of the right age, and he has the general profile of a player who might just take a while to find his stride in the majors. Sadly, though, none of that materialized. Zunino has crashed and burned, and PECOTA isn't sticking around to prop up his value any longer.

Preseason and Rest-of-Season PECOTA Projections, 2015

The Mariners were reportedly close to trading for Zunino's replacement early on Wednesday, and then, mysteriously, that never-reported deal fell apart. For now, it looks like Zunino will be the team's starting backstop a bit longer. It might not be long, though, before his own team gives up on him, just the way PECOTA has.

***

It's likely that our estimations of players change too much in small samples—and yes, half a season and change counts as a small sample. We know, though, that those half-seasons aren't completely without predictive and informative weight, and it's important that we have a projection system that corrects for every iota of information we can gather (without overreacting, of course). PECOTA thinks Bryce Harper has made a real leap to a new level, but it's pegging him for an OPS that would be 300-plus points off his first-half mark. That's the kind of thing looking at rest-of-season projections can help put into perspective. Even real changes (and they do exist, even in short time frames) are usually less important and of much smaller magnitude than we suspect. When we get better at grasping that, we'll be one small step closer to understanding the long, long season MLB plays, and we can avoid some of the false steps we've taken along that path in the past.