Blanks, who underwent a pilonidal cyst procedure in his lower back, began working out with the team in Kansas City on Sunday and continued his efforts in Oakland.
"We just wanted to make sure he was ready and capable of playing first base," Banister said. "We didn't want to just use him off the bench as a pinch-hitter."
Blanks, who is hitting .322 with three home runs, has not played since May 19.
"Ultimately I want to get as healthy as I can," Blanks said earlier this week. "My body feels pretty good right now, and I'm ready to take that out there."
• Outfielder Ryan Rua (right heel fracture) has hits in five of his first six rehab games at Round Rock.
Rick Eymer is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.