The Predators announced the signing Wednesday. Ekholm will earn $1.0375 million each of the next two seasons.
Ekholm, 24, had one goal and eight assists in 62 games as a rookie last season. He was one of only six NHL defensemen to play at least 50 games and to be assessed 10 or fewer penalty minutes.
He also played one game for the Predators in 2012-13 and appeared in two games with the team in 2011-12.