The Lassiter, along with the USS Potemkin, was one of the first two Starfleet vessels to respond to the Borg/Cyberman invasion of Delta IV on stardate 45635.2. The Lassiter was destroyed almost immediately. (TNG - Assimilation² comics: "Issue 1", "Issue 2")
- The artwork is very unclear, but appears to show one or both ships being destroyed or taking heavy damage to their saucer sections. The Lassiter is presumed to be an Excelsior-class based on this image, though that could represent a damaged Potemkin.
The work of the USS Enterprise-D crew and The Doctor and his traveling companions led to the prevention of the Borg/Cyberman alliance, so the events at Delta IV were erased from history beyond the people involved having maintained their memories. (TNG - Assimilation² comics: "Issue 6", "Issue 8")