Is there evidence that teams making many roster moves perform better than run differential would predict? Roster differential is catchy, but it begs the kind of question BP usually tries to answer.

The Orioles' run differential versus actual record is pretty staggering.

Their .563 record puts them well ahead of their Hit List Factor of .491 and Adjusted HLF of .511, and positively puts their Expected Winning Percentage of .445 to shame.

http://www.baseballprospectus.com/standings/
http://www.baseballprospectus.com/odds/

The fungibility of the roster is one possible contributor and I appreciated your bringing that to our attention.

One angle I was interested in was money, so I started playing around with the data.

At this point in the season the correlation between total opening day player salary, average salary, and aggregate change in salary from 2011 with winning percentage and games behind ranges from .18 to .24 (but they're lower in magnitude with change in payroll, at .09 to .14, which I think means the teams that upped their payroll the most are not getting commensurate bang for their buck).

Better correlated is pay with runs scored/runs allowed differential at .29 and .30.

Still higher correlations exist among payroll and the various win expectancies. BP's Expected Winning Percentage is correlated a whopping .41 with average salary and .40 with total salary, and HLF and AHLF are .32 to .36.

And right in the middle in terms of magnitude is the correlation between pay and something I wouldn't necessarily have expected...over performance on run differential.

I averaged the D1, D2, and D3 figures (into "DAVE") to measure over performance, and this was correlated .23 with total salary and .27 with average salary.

But it was a negative correlation. Lower paying teams are actually more likely to out-perform their run expectation.

In fact, the correlations of pay with actual winning percentage minus a) expected win percent, b) hit list factor, and c) adjusted hit list factor range from -.23 to -.31.

Do lower-paying teams have better "chemistry" (nebulous at best, and hard to do when you have as much roster churn as the Orioles)?

Is building a really good bullpen on the cheap key to success?

Does relative equality of pay lead to better team outcomes?

Or is it just a fluke?

Interesting note from Baltimore Sports Report: The Orioles have a -63 Run Differential between the Angels & Rangers, +44 vs. Everyone else. Could it just be a matter of them not matching up well with those two teams and that they are a slightly above avg team overall?

Some teams (perhaps, all?) abuse the disabled the list. Some D.L. injuries are made up to help with roster manipulation. I have heard this directly from the parents of a marginal major leaguer, who has been used this way.

WRT Arrieta, the reason he never got to be in the pen is because he made an emergency start the second day after that was announced and pitched well, and then his command fell apart. The straw that broke the camel's back was his July 5 start against the Angels, in which the Orioles gave him a 7-3 lead in the 4th and he proceeded to cough it right back up, walking the leadoff hitter and just serving up meatballs. After that performance, he was in Norfolk before he even handed Buck the ball.

Duquette went for depth, and it has paid off. He signed twice as many pitchers as he needed, and the team was rewarded (in fact, there's more that were performing well but weren't used in Baltimore - Villareal, Burke, Clark have pitched well enough to earn a look... except there was so little room they had to ship Neshek to Oakland, Socolovich to the Cubs, Bergesen to Arizona, Berken to DFA land). The Baltimore bullpen performed better could be reasonably expected. He made sure the "spare position parts" in Norfolk were ready and were not going to hurt the Orioles when they were called up. McLouth, Tolleson, Ford, Hall... Norfolk was used to repair those who weren't functioning well (Arrieta, Matusz, Britton, Hunter)... And to think he wasn't anywhere near the top of the list when the GM search began during the offseason.

"Wow, you were gone a long time" is one of the best throwaway lines I've read in ages. Well done.

As an Indians fan, I am having trouble wrapping my head around the concept, "Hitting Coach Einar Diaz."

My favorite part of his player card is that he has played for Cleveland, Texas, Montreal (!), St. Louis, and Los Angeles, and as such, is shown in a Pittsburgh Pirates hat. (Apparently he signed there but didn't make the big club.)

Love that line about playing "gin rummy" with the roster. Most teams would rather hold two sevens waiting all game on that third rather than break them up and chase something else.