Fantasy Baseball: 3 Things We Learned in Week 11

Amed Rosario has been red-hot at the dish and is worthy of a roster spot in fantasy. What else did we learn in Week 11?

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 eleventh scoring period of the fantasy baseball season.

The Justin Upton Leadoff Experiment

When you lose a player of Mike Trout's caliber for more than half a season, and you are languishing in third place behind two divisional teams likely headed to the postseason, why not start experimenting with your offense to see what kind of spark you can ignite. That's exactly what the Los Angeles Angels have done, booting David Fletcher down to the ninth spot and inserting Justin Upton into the leadoff position.

Upton, who has been in the majors since 2007, has 7,455 career plate appearances -- only 77 of those have come from the leadoff spot, all within the last month of play. But the Angels may have stumbled on to something, as Upton is slashing .333/.442/.651 in that position, good for a 1.092 OPS and 19 extra-base hits. Not surprisingly, Upton ranks first among active players with an increase of 219 to his expected weighted on-base average (xwOBA) over his last 50 plate appearances. His OPS+ sits at 181, or 81% above league average since his move to the top of the order. For some context, Barry Bonds' career OPS+ was 182, so Upton has essentially been playing at a Bondsian level for the better part of a month.

This is exactly what the Angels were looking for, someone to get on base in front of exit velocity god Shohei Ohtani and on-base expert Anthony Rendon. It may not be enough to overcome Trout's injury and propel them into the playoffs, but it sure has made their offense much more intimidating.

For the season, Upton's numbers still look more in line with his career numbers. In 225 total plate appearances this year, he has a .237 average, .333 on-base percentage, and .490 slugging percentage. But those good-not-great numbers mask the elite production we have seen from Upton in his last 20 games. If Upton is available in your league (he is only rostered in 57% of Yahoo leagues), he is an immediate, don't-stop-for-anything add to your roster. It might also be worth seeing what kind of trade could be worked out with an Upton manager, particularly if he is sitting on someone's bench who is otherwise happy with their outfielders.

Shane Bieber Spin Class

In all of the chaos of the crackdown on pitchers using various sticky substances to produce more spin and movement on their pitches, must we now add Shane Bieber to the list of hurlers that might start to see demonstrable drops in performance? If his last outing is any indication, fantasy managers should a least be slightly wary of what's to come. Yes, it is just a small one-start sample, but it's the only sample we have since this issue started to percolate across Major League Baseball and we need to start thinking about when some sets of data are actionable.

On Sunday, Bieber lined up against a very beatable Seattle Mariners lineup but was beat up for 10 hits, 2 walks, and 5 earned runs in less than 6 innings. If you look at his player breakdown on Baseball Savant for that game, you see some shocking drops in spin rate compared to his season averages.

We have already seen or heard of pitchers like Trevor Bauer, Gerrit Cole, and Corbin Burnes who might be caught up in this scandal (and have recently been hit hard), but it seems no ace is immune from feeling the effects of being able to produce less spin on their pitches. Does this one outing provide iron-clad evidence that Bieber is using some foreign substance? Absolutely not. But it certainly puts him on the watch list to see if this is just fatigue (Bieber has faced 30 more batters than any other pitcher in the majors this year), or something more nefarious.

In his previous start against the St. Louis Cardinals, Bieber's knuckle-curve, slider, and changeup all saw huge drops in spin rate against his season average as well, while the fastball sat right at his 2021 average. He was able to leave that game allowing only one run, so it's hard to say what's the most likely outcome going forward. But considering this is one of the top-shelf, elite pitchers in the game, it is worth monitoring very closely moving forward.

Add Amed Rosario

Amed Rosario (39% rostered in Yahoo leagues) - The shortstop position has sure taken a beating lately. Trevor Story spent significant time on the IL. Corey Seager looks to be out for quite some time. Javier Baez seems to perpetually be day-to-day. Francisco Lindor, while better lately, ranks outside the top 25 shortstops in points and roto leagues this year. If you're looking for a replacement or an upgrade up the middle, especially in roto formats, may I suggest Amed Rosario? He has been an under-the-radar elite performer for the past month and now seems to have a secure spot near the top of the Cleveland Indians order.

In the past 30 days, Rosario has accumulated 16 runs, 2 home runs, 4 steals, and 10 RBI plus a .355 average. Over a full season, that comes out to 96 runs, 12 homers, 24 steals, and 60 RBI. Even with a high batting average that isn't sustainable, give Rosario a .280 average with those numbers and you essentially have a poor man's Trea Turner from 2019, who was the sixth-best hitter in most roto formats that year. Rosario now has 29 games batting leadoff or in the two-hole this season, and he seems to have settled into the number two slot, where his slash line this season sits at .352/.398/.484.

Over his past 100 plate appearances, Rosario sits among the league leaders in improvement to xwOBA, jumping 60 points from .293 to .353 in that span. The spike is likely due to his increase in hard hits this year, as his Hard Hit percentage in 2021 (41.6%) is up 8.6% over last year and is the highest of his career. His performance near the top of the lineup has also helped elevate the offensive production for on-base machine Jose Ramirez, who also is near the top of the charts in improved xwOBA. For the season, the Indians rank 24th in team wOBA, but since June 1st, they have jumped up to 14th in the majors, ahead of teams like Atlanta, Boston and Tampa Bay. This is a strong buy candidate right now, and is worth the extra few bucks if he is available on waivers.