This week’s Roto-Relevant Research is not actually about research. It’s about the new custom filters at FanGraphs which should allow fantasy players to find good comparisons for the most interesting players on their waiver wires.

Take Travis Snider. The Pirates did.

He’s a 24-year old with more than 500 plate appearances, an ISO under .200 (.181 for Snider), a walk rate under 8% (7.6% for Snider), and a 25+% (27.2% for Snider) strikeout rate so far — just to describe him in a way that will make for easy filtering. That search gives you 16 players since 1974. Once you take out the center fielders (Cameron Maybin, Austin Jackson and the like), the middle infielders (Benji Gil and Danny Espinosa for example), and the catchers (John Buck and Jarrod Saltalamacchia) and try to focus on outfielders that won’t add much defensive value, the list of comparative players whittles all the way down to …

Laynce Nix, Wladimir Balentien, and Chad Hermansen. Uh-oh.

In Philadelphia, a group of trades have left 24-year-old Domonic Brown with a starting spot, finally. Brown’s a little different than Snider, even if he’s also a young guy with some tarnish to his formerly shiny prospect status. He doesn’t have the same power, so let’s set the ISO as <.160 (Brown has a career .146 ISO) and the walk rate over 9% (his is 10.7%). Strikeout rate here is tricky — Brown has a 21% career strikeout rate, and 20% is the league average most years. Let’s go 10% up and down and set the strikeout rate between 18-22%. Oh and since Brown has 281 PAs, we’ll set the cutoff at 250.

Brown’s group of outfielders is not as terrible as Snider’s. Dexter Fowler, Cliff Floyd and Roger Cedeno offer a believable group of interesting players that define his upside. On the downside, you have flameouts and backups like Rich Becker, Peter Bergeron, Pepe Mangual, John Hale, and Brad Komminsk. Looks like Brown’s chances are a little less than 50/50, although it’s worth noting that his ISO was actually the best of the group, and that the only others with ISOs over .140 in the group were Floyd and Fowler. If those two are this true comps, he has a fighter’s chance at relevancy yet.

It doesn’t have to be all doom and gloom with these things. You could use it to estimate the chance of a breakout, too.

For example, Starlin Castro. He’s likely to break personal records in home runs and stolen bases this year, and the idea that he could go 30/30 one year has been bandied about. Defining Castro, we have a 22-year-old shortstop who has put up an ISO over .100 (.125 for Castro) and a strikeout rate below 16% (14.2% for Castro). The walk rate being under 6% (4.8% for Castro) seems important, too — he needs to get on base to steal. Castro has over 1600 PAs so far, but that might kill our pool. Let’s set the over at 1000.

You get two players with this search: Garry Templeton and Jose Reyes.

Templeton’s first three years actually looked a lot like Castro’s, and he peaked in his fourth year: .314 batting average, 19 homers, 26 stolen bases in 1979. He was never that powerful again. We know Jose Reyes, of course, but it’s worth remembering that Reyes hit 19 home runs in his fourth season, which is a career-high to this date.

If you lower the threshold to 600 PAs, you get two interesting new names: Nomar Garciaparra and Ray Quinones. Nomar’s fourth season was probably his best fantasy season too: He hit .357 with 27 home runs and 14 stolen bases that year (1999). Quinones? He only lasted four seasons. Doesn’t seem a likely scenario for Castro. Since Reyes had more speed, and Nomar more power, Templeton really seems like the best comp for Castro, and he was good while he was young.

All of these players have had some health and/or longevity issues. It’s possible that Castro may peak soon, and that all that early play will take its toll on him.

Then again, we’re only comparing him to four players. Four like players, but four players. And that’s the trick with these things — you do your best to find comparison players, you try to set your thresholds right, and you will find that you get similar players back. But, as we’ve been taught since preschool, each of us is as unique as a snowflake. All these comps can do is give you a general idea of how similar snowflakes have performed in the past.