Edmonton released a statement confirming Pelss' passing and expressed their sadness at the loss.
"This is the news we feared," general manager Craig MacTavish said. "Kristians was an outstanding man and we feel terrible he has left us at such a young age. I can't imagine how painful this situation is for the Pelss family."
Pelss drowned in a river near his home in Riga, Latvia. He had returned home last week after the end of his season in the United States.
Local media reports indicated that Pelss jumped from a bridge into the river, according to ESPN. A spokesperson for the rescue services department confirmed they had received a call about a man jumping from the bridge, which began the investigation.
Pelss was an Oilers prospect, drafted in the seventh round of the 2010 NHL Draft from Latvia. He spent last season playing with the Oilers' AHL affiliate, the Oklahoma City Barons.