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.

MORE FROM YARDBARKER

Report: New Marlins owners will seriously consider trading Stanton

Report: Raiders CB Sean Smith charged with felony assault

Kevin Durant won’t visit White House with Trump in office

Red Sox owner wants to rename Yawkey Way

NFLPA leader: Lockout or strike in 2021 a ‘virtual certainty’

LIKE WHAT YOU SEE?
GET THE DAILY NEWSLETTER:

Ex-Cav: LeBron James-Kyrie Irving relationship can be fixed

Le’Veon Bell reportedly will return before regular season

Report: Aaron Donald has not ruled out skipping all of 2017

Reuben Foster injured same shoulder that scared teams off

Reporter: LeBron's reps ‘will/must lie to protect his image’

Multiple brawls erupt during 49ers, Broncos joint practice

The 'M! E! S! S! Mess! Mess! Mess!' quiz

Three Up, Three Down: Giancarlo Stanton won't stop hitting homers

NFL shifts blame for Zeke suspension to police and NFLPA

Box Score 8/17: Interleague games bring the fireworks

The 'Forget Calvin, bring back Jerry' quiz

The top 20 left-handed pitchers of all-time

Box Score 8/16: There is no stopping the Dodgers

The '27 up, 27 down' quiz

BIG3 Referee Hotline Bling: Charles Oakley slams the phone — and his opponents — down

The Cardinals have their season back by the unlikeliest of means

The BIG3 in L.A.: The reverse Danny Almonte comes to Staples Center

Box Score 8/15: Stanton's power surge has no end in sight

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 Yardbarker Privacy Policy and Terms of Service. You can opt out at any time. For more information, please see our Privacy Policy.

The 'M! E! S! S! Mess! Mess! Mess!' quiz

Three Up, Three Down: Giancarlo Stanton won't stop hitting homers

NFL shifts blame for Zeke suspension to police and NFLPA

The 'Forget Calvin, bring back Jerry' quiz

BIG3 Referee Hotline Bling: Charles Oakley slams the phone — and his opponents — down

The '27 up, 27 down' quiz

The Cardinals have their season back by the unlikeliest of means

The 'For Sale this fall: All of the awards' quiz

The BIG3 in L.A.: The reverse Danny Almonte comes to Staples Center

Getaway Day: It's an all-inclusive Wild Card party

Today's Best Stuff
For Publishers
Company Info
Help
Follow Yardbarker