Making A Small Sample Size Bigger For The Pirates

We are now 20 games into the season. Which means that a little over 12% of the season in the books.

While it’s nice to see some guys performing, like Josh Bell, who has a 152 wRC+ in 83 PA, it might be too small of a sample to assume he’s going to be a 152 wRC+ going forward. Or that the Pirates will have a historically good starting rotation. But how long has Josh Bell been good? How long has the Pirates rotation been stellar for?

I’m going to take a look at the Pirates past performance using totally arbitrary numbers. I’ve decided that for hitters, the last 300 PA is fair. And for pitchers, the last 10 GS for starters and 25 IP for relievers is a fair sample. It’s slightly more sophisticated than simply looking at the performance since the All-Star break, and should result in some interesting findings.

First up are the hitters.

Taking a look at this group, the first thing you probably notice is just how amazing Bryan Reynolds has been. Since July 7th, he has achieved a .412 on-base percentage (and will probably be sued by Shop412), and has done so while posting a slugging percentage over .500. Secondly, you probably notice that the Pirates as a whole have actually been quite good it seems, except for the two guys you can usually count on. Marte and Cervelli have really struggled, and Cervelli’s woes have carried over into 2019 so far. Elias Diaz isn’t Johnny Bench, but I think it’s possible we see a 60/40 split between Cervelli and Diaz this year.

Some omissions on this list include Jung Ho Kang, JB Shuck, Melky Cabrera, and Lonnie Chisenhall. To get 300 PA, we’d have to go back at least a couple of years for Kang, Shuck, and Chisenhall. As far as Melky Cabrera, he is a slightly above-average hitter with horrible speed and bad defense. He’s a 14-year vet, so his last 300 PA sample is far less interesting than his last 14 years of work.

Next up, the rotation.

The rotation has been outstanding to start the year. But their outstanding performance predates the 2019 regular season. The rotation has put up excellent numbers over their last 10 individual starts. The only thing worrisome here is Chris Archer’s home run rate, and maybe Mitch Keller’s strikeout to walk ratio. Neither are outstanding, but as a whole it’s pretty hard to find anything to complain about.

The notable omissions from this list include Jordan Lyles. You’d have to go back to May of last season to get a window of 10 starts, and given the changes that he’s had, it would be pretty meaningless to evaluate his last 10 starts. But hey, at least those last 3 starts have been worth evaluating.

And lastly, the RP.

Pretty good all around, minus Brault. Kela has been passed the eye test, for me at least, but the results since joining the Pirates haven’t been great. Steven Brault was optioned on Monday and brought back after Nick Burdi’s injury, and the table is a good explanation into why that happened. Vazquez, Crick, Kela, and Rodriguez make an excellent group of relievers. Burdi would have made this group possibly the best in the league, but his recent injury didn’t look good. Now the Pirates have an issue outside of the core four. Neither Kingham nor Liriano have much relieving experience. You can do worse as the 6th and 7th guys out of the pen, but the Pirates are currently without a reliable 5th option. Michael Feliz is a forgotten man in AAA, but he has been great lately. Maybe it’s a good time to give him another chance.