Buying Generic: Two Raking Rookies

A few weeks ago, I stole RotoGraphs contributor Joe Douglas’ idea (with his permission) as I pointed out that the “generic” Tommy Pham had provided surprisingly similar offensive production in his career to the “brand name” Michael Conforto. It was a fun exercise, and one that we’re going to do again today.

To set the stage, we’re going to talk about two rookies with outfield eligibility. One receives plenty of attention and hype; the other, not so much. Mr. Generic debuted in 2016 but is still considered a rookie this season, while Mr. Brand Name debuted in 2017. Here’s how they’ve fared so far this year:

The first thing that jumps out is the nearly 100-point difference in BABIP, and the fact that Mr. Generic’s BABIP is perhaps unsustainably high. More about that in a minute.

Also notice that both players have roughly the same wOBA and wRC+. They’ve had almost the same amount of plate appearances, too, and the 0.6 difference in WAR can be accounted for mostly because of defense and baserunning. While Mr. Brand Name gets most of the love, Mr. Generic has provided just as much offensive production in 2017.

The real concern is that BABIP for Mr. Generic. It seems like he may due for some serious regression in that department, which threatens the the legitimacy of this comparison. However, looking at each player’s RoS Depth Chart projections, which averages Steamer and ZiPS with playing time adjustments made by FanGraphs staff, we see the following:

While the BABIP for Mr. Generic is expected to decline, Mr. Brand Name is projected to lose over 100 points off his isolated power and 150 points off his slugging percentage. Overall, they’re projected to produce pretty much the same wOBA for the remainder of the year.

Who are these mysterious rookies? Time for the big reveal: Cody Bellinger is Mr. Brand Name, and Trey Mancini is Mr. Generic.

Bellinger is just 21 years old, and he’s hit 19 home runs is his first 50 games. He consistently dominated in the minor leagues, and it wouldn’t be a big surprise if he goes on to have a fabulous career, especially in the power department.

Mancini, meanwhile, is 25 years old, and he also dominated at every level of the minor leagues. The BABIP will likely fall, but he’s still projected to be an above-average hitter in a hitter-friendly ballpark, and there’s value to that.

The younger (and more powerful) Bellinger probably has the higher ceiling. If he continues to hit homers at this ridiculous pace, the projections will adjust, and he’ll clearly be the better bet moving forward.

The point, however, is that Bellinger and Mancini have produced roughly the same value on offense this season, and that the projections forecast more of the same RoS. This is particularly relevant in fantasy leagues that use linear weights to reward offensive contributions, instead counting stats like home runs and runs batted in.

In so-called points leagues, Mancini has been Bellinger’s equal this year, and the projections suggest it could be pretty close for the remainder of the year as well.

As more and more fantasy teams are falling out of contention and deciding to sell, it may be wise not to buy the brand name Bellinger, but to buy generic the Mancini (then use the savings on something else). While Bellinger may have more hype and upside, he and Mancini seem to be more similar than people realize.

All stats as of June 19 (before games).