Callahan officially announced his retirement on social media Wednesday.

Callahan remains on long-term injured reserve, with his contract set to end in July.

The Lightning traded Callahan (back) and a 2020 fifth-round pick to the Senators in exchange for Mike Condon and a 2020 sixth-round pick Tuesday.

The Lightning placed Callahan on long-term injured reserve Thursday due to a degenerative disc disease of the lumbar spine.

Callahan played two of the Lightning's first-round games against the Blue Jackets, finishing with four penalty minutes and four shots in limited ice time.

Callahan (undisclosed) will slot back into the lineup for Sunday's Game 3 matchup with Columbus.

Callahan (undisclosed) remained among the extras at Thursday's morning skate, indicating he should sit out again for Game 2 against the Blue Jackets, Erik Erlendsson of LightningInsider.com reports.

Callahan (undisclosed) isn't expected to play against the Blue Jackets on Wednesday for Game 1 of the conference quarterfinals, Joe Smith of The Athletic reports.

Callahan (undisclosed) was not on the ice at Monday's practice, reports TampaBayLightning.com.

Callahan (undisclosed) left Saturday's game early in the second period and did not return.