Is backfield a word in the Scrabble Dictionary

Yes, backfield is playable

...and is worth 24 points.

Found in the following dictionaries

Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)

"Backfield" Definition

noun

Football The area in which these players line up.
Football The players stationed behind the line of scrimmage.
Football The positions filled by these players.
Sports The primarily defensive players on a soccer, field hockey, or Rugby team.
The football players whose positions are behind the line of scrimmage.