The word infielders is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 16
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (36 words)
defiers, defiler, defiles, definer, defines, deifier, deifies, deniers, edifier, edifies, eleidin, felines, fenders, fielder, finders, flensed, flenser, friends, infidel, infield, insider, lenders, linseed, redline, refiled, refiles, refinds, refined, refines, reflies, reified, reifies, reliefs, relined, relines, slender