The deal offers further clarity as to how the Raptors' front court will look next season.
Boucher's decision to return comes on the heels of Marc Gasol reportedly finalizing a deal with the Los Angeles Lakers, and the Raptors bringing in free-agent centre Aron Baynes.
According to Blake Murphy of The Athletic, the second year of Boucher's deal is not guaranteed. Structuring the contract in such a way will maintain the Raptors' flexibility for next off-season.
The 27-year-old averaged 6.6 points, 4.5 rebounds and one block per game last season.