The 27-year-old Lehtera had 14 goals and 30 assists in 75 games in his first NHL season, and ranked second on the team with a plus-21 rating. He had two assists in five playoff games.
Lehtera was a third-round draft pick in 2008 and spent the first seven seasons of his pro career in Europe.
The Blues also signed defenseman Chris Butler to a one-year deal Wednesday. The 28-year-old Butler had three goals and six assists in 33 games last season. He's played in seven seasons including stints with Calgary and Buffalo.
St. Louis also signed forward Cody Beach to a one-year, two-way contract.