Lindgren was not qualified by the Penguins on Monday and will become a free agent.
Lindgren was included in a six-player trade Tuesday which saw him head to Pittsburgh from Toronto along with Kasperi Kapanen and Pontus Aberg in a swap for Evan Rodrigues, Filip Hallander, David Warsofsky and a 2020 first-round pick.
Toronto has loaned Lindgren to Modo of the SHL.
As expected, Lindgren (undisclosed) was loaned out to HPK Hameenlinna on Saturday.
Lindgren -- who was held out of rookie game due to a minor injury -- is planning to return to HPK Hameenlinna for the upcoming season, Scott Wheeler of The Athletic reports.