"Everything felt really good," Walker said. "I still threw with the tape on, so I didn't get a real feel for it, but mechanically I thought it was the best I've felt all year."
Walker has thrown with tape covering the blister so as not to aggravate it any further. On Wednesday he threw between 60 and 65 pitches.
D-backs manager Torey Lovullo said the team would evaluate Walker in the next 24-48 hours and then decide whether his next step will be to rejoin the rotation or if he needs to give the blister more time to heal.
Walker said he would leave the tape on his finger if he throws a side session between now and his next start. A pitcher cannot wear tape or a covering of any kind on his hand in a Major League game.
"We just don't want to re-aggravate it before I go back out there," Walker said. "I think we all know what might happen -- I might get a blister again. If we can lessen the friction before the next start, we should be good."
Outfielder A.J. Pollock stepped up his rehab from a Grade 1 strain of his right groin when he ran on the field at about 75 percent effort Wednesday. Sprinting and running the bases at full speed are the final hurdles for Pollock to clear.