Falu said he also could play the outfield, but didn't do so for Nashville because they have a glut of outfielders.
Manager Ron Roenicke said he liked Falu's versatility and that he was a switch-hitter.
"I was looking at his numbers and he's not a strikeout guy," Roenicke said. "I feel like coming off the bench I can put him in to do some different things and put the ball in play."
Falu signed as a free agent in the offseason after spending several years in the Royals organization. In 25 games for the Royals over 2012-13, Falu batted .337 (30-for-89) with no home runs and seven RBIs.
In 38 games at Nashville, Falu was batting .288 with one home run and eight RBIs.