Rumour has it former Celtics big man Greg Monroe could be on his way to Toronto in the midst of free agency.
This has the potential to be a great move for both sides, with Monroe filling out the rotation of big men here in the North. He could certainly be a good complementary player to Serge Ibaka and JV, both threats from deep.
If you throw Valanciunas and Monroe on the court in the same lineup, with Pascal Siakam, CJ Miles and one of Delon Wright or Fred VanVleet, it could quite possibly be an overpowering supersized lineup, the perfect lineup to spite the modern concept of "small ball". Valanciunas would provide spacing with his newfound three-point stroke, and Monroe would likely bang out with opposing big men down low.
Pairing Monroe with Ibaka could also work, with both guys providing a defensive presence in the paint as rim-protectors. Ibaka will space the floor on offence, so long as his shot can fall consistently this year, a rare occurrence last season.
Pairing Monroe with Siakam would not be ideal, seeing as both neither can shoot the three at a decent rate, effectively destroying spacing.
All in all, I'd say that it might not be the best decision for the Raptors, seeing as a lineup with JV and Monroe would have a difficult time guarding small ball lineups, (although they would likely dominate on the offensive end) a lineup with Monroe and Ibaka would have similar issues on the defensive end, (however they would be an absolute force against bigger squads) and finally a lineup with Monroe and Pascal would have zero spacing on offense.