Help w/ reading the cards - gb A vs. gb B

Musial gets injured on a gb with Carew on 2nd base. Carew advanced to 3rd.......
Does that mean Musial's injury occurred on a gb B? Or, does the gb A DP only occur on a force out from 1B?

You got it ace.

http://www.baseballthinkfactory.org/btf ... mrules.htm

Read the rules....
As I read it, no definite conclusion. Could be gbA or gb B, depending on who fielded the ball. The Mystery League doesn';t specify that in the PBP??

It is a mystery. you are getting deep into the stats. Maybe too deep. splits and BB can help.