Using xPA to Evaluate Lineup Movers: Victor Robles

After introducing xPA (expected plate appearances), Nicklaus Gaut uses this metric to look at Washington Nationals outfielder Victor Robles to evaluate how much a move to the leadoff lineup spot could change his overall value. Using historical data for team runs scored, xPA aims to properly value lineup spots according to projected team offense.

We don't need to talk about how much a player's lineup spot matters. The higher you are, the more times a game you'll bat. Plus, you'll almost necessarily be surrounded by better players. That simply means more opportunities to pile up fantasy stats.

Consider Ronald Acuna Jr., who was on pace for 658 plate appearances after batting cleanup for the first 36 games of 2019 and averaging 4.33 PA/G. Acuna finished with 715 PA after moving to leadoff and averaging 4.72 PA/G for the rest of the season. That pace would've equaled 736 PA over his 156 games, a near 12% increase over batting cleanup.

Using the recently introduced xPA (expected plate appearances), which aims to project plate appearances based on both team offense and spot in the lineup - I'm going to use this series to look at a few fantasy favorites whose ultimate value could be tied to if and when they ascend to the top of the order. And even if they do, how much will it actually matter? Let's start with a top-five prospect from a year ago, Victor Robles.

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Breakout Pending

One has to wonder about the alternate timeline where Robles isn't usurped by Juan Soto in Washinton's prospect pecking order after injuring his elbow in the fourth game of 2018. His call-up seemed virtually a Super-Two formality prior to the injury but then the elbow cost him three months and Soto started his meteoric rise after getting the call that very well would've gone to Robles. In other timelines, Robles is entering his third full year in the majors, instead of the second and may have already started to realize the potential that his promised tools have still only hinted at.

An elite leadoff hitter his entire minor league career, Robles spent most of his rookie year in the bottom third of the order, with 398 of his 617 plate-appearances coming from the seventh, eighth, and ninth spots. He may have lacked the bombast of Soto's rookie campaign but he certainly wasn't a slouch, stealing 28 bases and throwing around some premium leather in centerfield. Robles also hit 17 HR, a welcome sight after his weakest tool led to just a combined five home runs at Double- and Triple-A.

Possessing the profile and skills of a prototypical leadoff hitter, signs started to point in that direction entering spring this year. Looking to fill the three-hole left by now-Angel Anthony Rendon, manager Dave Martinez indicated they'd be open to exploring using Trea Turner in the vacancy, with Robles taking over his spot at the top.

As Things Stand

Spring training didn't give us many answers with Robles only appearing in six games (15 PA) between dealing with a minor injury in his side and the games eventually being canceled. But Robles hit leadoff in two of his three starts and hit second in the other game. Turner only appeared in two games with Robles, batting leadoff in one with Robles hitting second and third in the other with Robles leading off.

Current Projected Lineup

Roster Resource currently has Robles penciled in to bat fifth even if it seems fairly obvious that he's one of the Nationals four best offensive options. If Martinez goes outside of the box and bats Turner third, it's easy to imagine the tantalizing fantasy implications of a lineup that goes Robles, Eaton, Turner, and Soto. Three on-base machines, two with elite speed, and an MVP-caliber masher? That's what you call a fantasy-friendly lineup.

But Martinez could elect to play it traditionally and keep the one-two punch of Turner and Eaton at the top, with the three-hole instead being filled by the split-sensitive platoon of Starlin Castro and Eric Thames. Or perhaps even (cough-cough) the suddenly prolific Howie Kendrick.

So what production differences can we expect between Robles batting leadoff and in the five-hole? Accepted historical lineup analysis says that each spot you move up will result in a 0.10 - 0.11 PA/G boost, or around 16 PA per 162 games. However, that doesn't account for the impact the amount of team runs scored will have on the average plate appearances that each lineup spot will garner.

What the Projections Say

Looking at four of the most popular projection systems (Steamer, ATC, The BAT, and Depth Charts) Robles is projected for between 619 and 666 PA with the production rates staying mostly in line with each other.

The speed is obviously Robles' carrying trait, with stolen bases becoming more and more of a precious commodity in fantasy. To give his stolen base projections some context, none of the systems above project more than six players to cross the 30 SB threshold in 2020. However, nothing else really jumps off the page, so just how much value would the above projections translate to?

Using the Fangraphs auction calculator, we can translate the above lines into dollar-values for a standard 12-team league, with five outfielders, two infield swing-positions, and one utility slot. Included along with each system's projected dollar-values for Robles, are both his overall rank and outfielder rank:

Besides The BAT, no one else sees Robles as a top-50 player and only one other system projects him as even a top-20 outfielder. Considering he's being drafted around a 60 ADP in NFBC leagues, it seems like stolen bases will need to shoulder much of the return-on-investment burden and close the perceived gap between price and value.

Adjusting to xPA

In case you missed it, xPA aims to place a PA/G value on every lineup spot, using historical averages for team runs. Basically, it's a tool to quantify how many more plate-appearances on average you can expect from the Yankees #3 hitter compared to his counterpart on the Royals. And so on. In short:

If Team A scores Y runs, then the player in Lineup spot Z will average xPA/G. 

Using my previously laid out methodologies, let's take a look at the differences between Robles' xPA and his projected PA, as well as what the differences could be between hitting first and fifth for the Nationals. xPA averages six systems (PECOTA and Razzball, in addition to the four aforementioned) for projected team runs, with each team being put into one of 10, 50-run "bins," with the first one starting at 500-550 runs. This is important because what bin a team is in determines how high the average PA/G will be for each lineup spot.

Projected Team Offense

Along with the actual lineup spot, a team's projected runs will underpin the xPA projections for each spot in the order. So how many more appearances Robles would see after a move from first to fifth will largely depend on how many run the Nationals score. Are they the same caliber of offense as they were with Anthony Rendon in 2019, when their 873 runs were the sixth-most in baseball?

2020 Team Run Projections and Ranks

Middling is the word you're looking for. The above projections seem to see Washington's offense as more middle of the pack than elite. PECOTA straight-up hates them. xPA takes the average of the above systems in order to put Washinton in their appropriate run-scoring bin. In this case, they average out to Bin F (750-799 runs), the fifth-highest of the 10 bins.

Based on historical averages and projected team runs, here are the xPA/G for each spot in Washington's lineup. Also included is Robles' xPA at each spot, based on his average projection of 150 games played:

Given how average Washington's offense projects to be, it's not a big surprise to see that the PA/G differences between spots are only slightly above what the averages are known to be without considering runs scored.  While that's not great news for those hoping for a big value bump from Robles moving on up, 708 PA would still be a significant increase when compared to what the projection systems currently call for.

By adjusting the previous dollar values and projections from before to the hypothetical 708 xPA that we assume a leading-off Robles would collect, we can directly compare production at fifth to possible production at first. To do this I simply took each projection system's per/PA rates and extrapolated them to the new PA.

Keep in mind the fuzzy math we do when extrapolating. The adjusted projections below assume that the per-PA rates would stay static if Robles were to move to leadoff, both in projections as well as on-field production. Like Acuna before him, it's easy to imagine that Robles would likely finish with more stolen bases from leadoff as opposed to fifth. It's also easy to see that a bump in runs scored would be expected, as well as a drop in RBI.

Verdict

I believe the only way Robles can out-earn his draft price is by blowing up his stolen base total. A move to leadoff would certainly help his chances but Washington's offense isn't likely to produce enough for the added plate appearances to make a big enough difference in the other categories.

Robles' draft price has stayed remarkably steady through the offseason, with his 58 ADP in NFBC Champions leagues over the month of March just two spots lower than it was in December. I'll pay (and have paid) his fifth-round price but that's more due to my belief in an early need for speed. My overall expectations are being held in check by Washington's mediocre offense and I'm not going to get carried away thinking it'll be something more... unless they play Howie Kendrick more, of course.

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