https://www.nhl.com/player/jakob-pelletier-8481592
NHL.com — 5'9", 160. But maybe things have changed since that was last updated.
Either way, it doesn't really matter. Size shouldn't play a massive role in prospect evaluation. If you can play, you can play, no matter how big you are. There are plenty of small players in this league. They win the Stanley Cup every year.