The Pistons trade 8th overall pick to the Boston Celtics. Celtics send back Kelly Olynyk, 16th & 33rd overall picks.

SB Nation's Celtics blog, CelticsBlog, explains the pick:

The Celtics have a lot of picks and young players but needed to upgrade the talent on the roster. Moving up allowed them to pick the 7 footer Porzingis who some feel could wind up being the best player from this draft. His shooting and rim-protection potential fit nicely with the system that Brad Stevens is implementing. Kelly Olynyk is a nice rotation player but has a limited ceiling and shares time with Sullinger already. This trade makes this young team even less experienced in the short term, but should be a long term upgrade. Pistons trade 8th overall pick to the Boston Celtics. Celtics send back Kelly Olynyk, 16th & 33rd overall picks. Celtics taking Porzingis.

The Celtics have a lot of picks and young players but needed to upgrade the talent on the roster. Moving up allowed them to pick the 7 footer Porzingis who some feel could wind up being the best player from this draft. His shooting and rim-protection potential fit nicely with the system that Brad Stevens is implementing. The downside is that he's going to take time to develop.

Kelly Olynyk is a nice rotation player but has a limited ceiling and shares time with Sullinger (and others) already. This trade makes this young team even less experienced in the short term, but should be a long term upgrade. There's also a very good chance that a lot other moves could be on the horizon come July 1st.