Blanks recently completed a 10-game stint with Class A Lake Elsinore, where he hit .270 in 37 at-bats with six walks and 12 strikeouts.
Blanks played his first game with Portland on Monday and started in left field. He went 1-for-3 with a strikeout.
Manager Bud Black said there's no timeline for how long Blanks will be in Portland, but the Padres will have to make a decision by Sunday, when his allotted 20-day stint in the Minor Leagues on rehab expires -- that means either recalling him back to the Majors or optioning him to Portland.
What do the Padres want to see from Blanks?
"Performance, good at-bats, hard contact, cut down on strikeouts," Black said.
San Diego's opening day starter in left field, Blanks was hitting .157 in 33 games in the bigs. He struggled with contact, striking out 46 times in 102 at-bats.
The team will hand out Kyle Blanks bobblehead dolls Saturday to the first 25,000 fans.