Originally posted on Fangraphs  |  Last updated 1/28/13

According to Kevin Towers, a few days ago he was prepared to move on without having traded Justin Upton, as he wasn’t finding enough value on the market. In lieu of an Upton trade, the Diamondbacks presumably would’ve made a Jason Kubel trade, presumably with the Orioles. But things changed, and they must have changed swiftly — on Thursday, the Diamondbacks officially announced an Upton trade with the Braves, as Justin will join his brother B.J. in the Atlanta outfield. Or, this, in other words. Dave already wrote about the trade overall, from both sides. Mike Newman already took a look at the prospects involved. I, personally, got curious about the brother angle. This was something Justin was hoping for; he turned down a trade to Seattle, hoping for a trade somewhere else, somewhere more familiar, somewhere closer to home. Speculation was that he wanted Atlanta more than anything else. It’s an odd quirk that Upton will play beside his own brother. But I found myself wondering if the psychology involved has any effect on performance. In short: historically, have players gotten better when they’ve been teammates with a sibling? On one hand, it would be surprising if they did; on the other hand, it would be surprising if they didn’t. Players are always talking about the importance of comfort. What could be more comfortable than playing with family? It’s unusual for brothers to be teammates in the major leagues, but it’s hardly unprecedented. See this information from Baseball Almanac. There have been plenty of teammate brothers, and there have been a couple teammate father and sons. Any study is still going to be based upon a limited sample, but at least there is a sample, so we might as well see what we see. I identified brothers who became teammates after already having gained major-league experience. In this way, I could track their performances in the year before they became teammates, and in the year after they became teammates. It stands to reason this is where we could see an effect. For hitters, I looked at wRC+, and for pitchers, I looked at ERA-. I considered post-war major-league baseball, because I’m not real interested in what happened before then, and I set arbitrary minimums of 100 plate appearances for hitters and 40 innings for pitchers. In the event that brothers became teammates, split, and then later became teammates again, I counted them multiple times. Understand that we’re working with a very limited sample. Understand that this isn’t fantastic science, and understand that there are multiple potential sources of error. But what you want are results, so here are some results: Hitters Year before teammates: 110 average wRC+ Year after teammates: 114 average wRC+ Pitchers Year before teammates: 93 average ERA- Year after teammates: 102 average ERA- There’s nothing real eye-opening. The pitchers have actually gotten worse, but our sample is 17 individual player seasons, our difference is nine points, and our statistic is based around ERA, which as you know includes a lot of noise. With the hitters, there’s a four-point improvement, but given all the noise we can’t reach conclusions from that. We don’t have evidence that players hit a lot better, nor do we have evidence of the opposite. What our evidence suggests is that players remain more or less the same, which would be fairly intuitive. Jason Giambi took a big step forward when he was joined by brother Jeremy in Oakland in 2000. Roberto Alomar and Sandy Alomar improved between 1998 and 1999. But then, Scott Hairston struggled alongside Jerry in 2010. Adam LaRoche didn’t do much for Andy LaRoche. The results are mixed, just as you’d think they would be. I’m sure it’s a neat experience to play on the same major-league team as a sibling. Even if you aren’t particularly fond of that sibling. That doesn’t mean a player’s likely to improve, though, at least not because of the teammate reason. It turns out baseball is a complicated game the outcomes of which can’t be determined by one’s emotional state. Play with a brother in April and, chances are, come July or August, it just feels like regular baseball. Chances are even in April it just feels like regular baseball, with maybe a good friend in the clubhouse. Of course, what applies generally doesn’t have to apply specifically, and the Upton brothers are unique, like all sets of brothers. Both are known for their incredible raw skillsets, and both are known for not consistently reaching their ceilings. Maybe each will be motivated in Atlanta by the presence of the other. Or maybe B.J. will just be happy to be away from Tampa, and Justin will just be happy to be away from Arizona. Maybe they don’t improve. Maybe they stay the same, or even get worse. At the end of the day, they’re just two teammates in major-league baseball who know each other pretty well. It’s going to be weird for Jason Heyward, though. No one likes feeling excluded.

Ios_download En_app_rgb_wo_45

Houston taped SMU jerseys to ground as motivational tactic

Lionel Messi cleared of tax fraud charges

Clemson WR Mike Williams 'likely' out for rest of season

Week 5 NFL game watchability rankings

Gregg Popovich makes LaMarcus Aldridge sit out practice

Greg Hardy excited to face Tom Brady because of wife Gisele


Aldon Smith pleads not guilty to hit-and-run DUI

Why the Thunder starters need to stay healthy this year

Josh McCown, Craig Robertson defend Joe Haden

Jimmy Butler cannot believe teams game-plan for him

James Harden: I know I was the MVP, that’s 100 percent given

Five questions about the 2015 American League Wild Card game

Rick Ross still wants to be part-owner of Miami Dolphins

Usain Bolt and USC star Adoree' Jackson got to meet

Texas QB downplays talk of infighting within team

Miami's Twitter account bombarded by FSU fans

Six of the biggest NFL disappointments this season

Arrieta-Cole, objectively one of best playoff matchups ever

The weakest undefeated team

The controversy and numbers behind the 'CONCACAF Cup'

Belichick: Patriots use rulebook to ‘maximize our opportunities’

Bronson Arroyo’s former assistant arrested for allegedly selling pitcher’s boat illegally

Jets coach Bowles’ sweet tooth lands him cookie care package

Report: CC Sabathia may have been drinking around clubhouse

Roddy White: I want to catch passes

MLB News
Delivered to your inbox
You'll also receive Yardbarker's daily Top 10, featuring the best sports stories from around the web. Customize your newsletter to get articles on your favorite sports and teams. And the best part? It's free!

By clicking "Sign Me Up", you have read and agreed to the Fox Sports Digital Privacy Policy and Terms of Use. You can opt out at any time. For more information, please see our Privacy Policy.
Get it now!
Ios_download En_app_rgb_wo_45

Arrieta-Cole, objectively one of best playoff matchups ever

The controversy and numbers behind the 'CONCACAF Cup'

Why the Thunder starters need to stay healthy

Roddy White: I want to catch passes

Five questions about the 2015 AL Wild Card game

Bowling Green State coach saves motorist from serious injury

Bills defenders: Odell Beckham Jr. is a prima donna

Lifelong Yankees fan disses Alex Rodriguez in obituary

Trail Blazers honor Umpqua Community College victims

CC Sabathia and the humanity of athletes

Today's Best Stuff
For Publishers
Company Info
Follow Yardbarker