The 30-year-old received the injection following conversations with multiple specialists, who also put the ball-handler on a 12-week strengthening program.
Walker missed nine of the Celtics' last 17 games before the league's hiatus last season due to a knee issue. The discomfort persisted through the stoppage, causing him to miss multiple team practices and two of Boston's eight seeding games. Walker operated under a minutes restriction when he returned, though that limit was lifted for the playoffs.
Celtics president Danny Ainge says Walker has been in good spirits since speaking with the specialists but admits he's unsure if the guard's ailment will be a long-term concern.
"I think this year will tell us a lot more," Ainge said Tuesday, according to ESPN's Tim Bontemps.
The Celtics also announced that new center Tristan Thompson will be limited in the first week of training camp after he suffered a hamstring strain during an offseason workout.
Teams around the league are expected to open camp Tuesday.
The 2020-21 season begins Dec. 22.