As a result of the injection, the right-hander will not make his final rehab start for Triple-A Pawtucket on Tuesday. Matsuzaka will be shut down for a minimum of seven days and will then have clearance to start another 30-day Minor League rehab assignment.
"The same area maybe flared up about three weeks ago," Matsuzaka said through an interpreter. "The same symptoms seemed to clear up, but they came back again. It restricts my movement. That's why I got the shot and hopefully it gets better from here. My rehab, so far, has been going really well. It is a setback, and it's a little disappointing, but hopefully the shot takes care of it and I can continue my rehab from there."
Matsuzaka said he is already feeling better because of the injection. His goal is to pitch a bullpen session as soon as possible.
The Red Sox have not put a timetable on his return. Matsuzaka doesn't plan to return until he is fully healthy.
"I don't want to, and I don't think I can, pitch until I am at 100 percent physically and mentally, and that's the type of patience I need to continue working with," said Matsuzaka, who was 0-2 with a 4.62 ERA in five rehab starts. "I haven't felt 100 percent yet, but I have felt that I'm getting approaching 100 percent, getting closer to 100 percent."