Quarterback Flacco has suffered criticism for his performance during the defeat to the Cleveland Browns, and Harbaugh has said that he needs to get the ball out quicker as the blockers are doing a good job.
"I feel like our O-line blocked a lot better than the result might have shown in terms of number of yards," Harbaugh told The Baltimore Sun. "When you watch the tape, there are a lot of really good blocks going on there.
"But the quarterbacks have got to get the ball out, and they've got to find ways to protect themselves with 'hot' throws and things like that too.
"Joe generally does a good job of that. Yes, we need him to take fewer hits, but we'll do that by getting the ball out quickly, continuing to work on our technique in pass protection and picking up blitzes."
The reigning Super Bowl champions host the Cincinnati Bengals on Sunday.