The team said Blake was expected to remain in the hospital for several days. He is averaging 7.6 points, 2.4 rebounds and 3.6 assists this season.
The Blazers have been beset by injuries and have received two hardship roster exemptions from the league.
Forward LaMarcus Aldridge sprained his left ankle in the first quarter of the Blazers' 103-99 victory over the Los Angeles Clippers on Wednesday. He is doubtful for Saturday night's game against Golden State.
Portland signed forward Anthony Tolliver with an injury exemption, then waived him and added forward Shavlik Randolph, who played for the Blazers last season. It is unclear whether they will use the second exemption.