Fantasy Baseball: 3 Things We Learned in Week 13

Baseball fans love their stats. We devour them, dissect them, and build our fantasy rosters around them. Each week of the 2021 baseball season, we will be gifted with another statistical sample size of pitches, plate appearances, and playing time. Knowing it often takes hundreds or even thousands of pitches or batted-ball events for trends to normalize, how should fantasy managers adjust to the ebbs and flows of weekly player performance?

Each week during this season, this piece will look at trends that have emerged over the past week and determine if it is signal or noise moving forward. What is prescriptive in helping build winning fantasy teams and what can be ignored as small sample size noise? Hopefully, we can make sense of what has just happened to help us make smarter roster and free agent budget decisions.

Let's take a look at some of the data from the 13th scoring period of the fantasy baseball season.

Get What You Can For Yuli Gurriel

Say what you will about the Houston Astros and their past transgressions, but their offense is just on another level right now. As a team, their weighted runs created (wRC+) number of 125 is 14 points better than any other team in the Majors. They have the highest team on-base percentage and slugging percentage, complimenting it by being the only team to strike out in less than 20% of their plate appearances this season (18.8%).

When the Astros lost George Springer this offseason, it was speculated that the downgrade from Springer to someone like Myles Straw would be massive and impact the whole offense. That decidedly hasn't happened so far and one of the main catalysts this year has been 37-year-old first baseman Yuli Gurriel. Gurriel -- who came to the Majors as a 32-year-old Cuban star in 2016 -- is raking with a .333 batting average, .396 on-base percentage, 10.6% walk rate, and minuscule 9.2% strikeout rate. Each of these are quite comfortably the best numbers of his career.

Gurriel has been an elite fantasy asset this year, especially in points leagues where he ranks as the fifth-best first baseman. But despite being part of an offensive juggernaut, it is probably time to start shopping Gurriel considering how lucky he has been in 2021.

First, his batting average on balls in play is an unsustainable .332 (league average this year is .289). This means his expected batting average through the first half should have been around .282. His hard-hit percentage and line-drive percentage are all the lowest they have been in at least three years, while his ground-ball rate is the highest in three years, all contributing to the conclusion that he shouldn't be crushing quite like he is. The numbers really stand out in his batted ball data, according to Baseball Savant.

Gurriel has never been a barrel rate or exit velocity darling, so are we to believe that all of a sudden he figured out how to hit the ball incredibly hard at age 37? Something is amiss through his first half and he's likely to come back to earth over the final 81 games. But if there is a fantasy manager who needs average and RBI in rotisserie formats or is short a first baseman or corner infielder in points leagues, now is the time to start making some offers.

The Boston Ace in Hiding

Any discussion of "expected" statistics should be taken with a huge grain of salt. In the Statcast era, there are expected statistics for almost everything. Expected batting average (xBA), expected ERA (xERA), expected weighted on-base average (xwOBA) -- you get the idea. Fortunately, the conversation around expected statistics has been evolving to a more mature understanding. We know now that just because Alex Kirilloff has an expected slugging percentage (xSLG) of .600 (which he does right now) doesn't mean he's going to just slug .600 the rest of the way.

Expected statistics are not predictive. Rather, they tell the story about what we could or should have seen based on the batting or pitching outcomes that have already happened. They help us set a baseline or better understanding for what a player could achieve moving forward with the same type of production. And with that stage set, if expected statistics can tell us anything or help us identify hidden gems, we need to keep a close eye on Boston Red Sox pitcher Eduardo Rodriguez.

Rodriguez's season to date has not gone as fantasy managers expected. In 2017-2019, the Red Sox ace had an ERA between 3.81 and 4.19 and an ERA+ between 109-128. This year, his ERA has ballooned to 5.83, and his ERA+ sits at 77 or 23% below league average. But despite the ugly surface numbers, perhaps no single pitcher has been as unlucky as Rodriguez through the first half of the season.

Only two pitchers rank in the top 10 largest differences between their actual seasonal batting average and xBA, their slugging percentage and xSLG, their ERA and xERA, and their wOBA and xwOBA: Kyle Freeland and Rodriguez. And since fantasy managers are conditioned straight out of the womb to avoid Colorado starting pitchers, that leaves just Rodriguez as the object of our desire. Rodriguez's expected ERA is almost 2.5 runs less than his 5.83 figure so far, while his expected slugging is almost 100 points lower than the outcomes produced so far.

He has shown signs of breaking out of the slump, so the buy-low window may be closing soon. Last week, he posted two quality starts against the Tampa Bay Rays and New York Yankees (two strong offenses), striking out 15 batters across 12 innings, walking only 1 batter, and allowing just 5 earned runs. Rodriguez remains available in 45% of Yahoo leagues, so it's worth checking to see if he is still available. Otherwise, time may be running out to acquire Rodriguez from a manager who is frustrated by the inflated numbers so far.

Add Akil Baddoo

Akil Baddoo (21% rostered in Yahoo leagues) - Back in early April, Akil Baddoo burst onto the major league scene, blasting 4 home runs with 10 RBI and a .391 batting average in his first eight games, causing fantasy managers to throw FAB dollars his way like they were in a Mardi Gras parade. By his 24th game, however, Baddoo was still stuck on four home runs and his average had plummeted to .192. Pitchers were starting to discover the holes in the talented prospect's swing, and it would be up to Baddoo to see if he could counter their pitching strategies with his own adjustments.

After languishing with a batting average below .220 and an on-base percentage below .300 until mid-May, things have finally started to turn around for Baddoo, particularly in the past week. He got a couple of days off to clear his head after May 18, but since he returned to the Tigers' lineup on May 22nd, he has been hitting the cover off of the ball, per Baseball Reference.

He may only have one home run in that span, but a triple slash line of .342/.467.507 will get the job done in any fantasy format, and the five steals are just the cherry on top. What makes this even more impressive is that the Detroit Tigers have recently moved Baddoo to one of the top two spots in the order, after frequently batting him seventh through ninth for most of May.

Despite the relatively low number of home runs and RBI the past 15 days, Baddoo still ranks as the 30th-best outfielder in traditional Yahoo rotisserie formats in that span, powered by a .378 average, seven runs, and three stolen bases. If Baddoo can find his power stroke again in the second half of the season and pair it with one-to-two steals per week, we could easily be looking at a top-30 outfielder the rest of the way. Chances are that he is free for the taking in your fantasy league.