Harbaugh didn't have any details of when or where the throwing sessions will occur.
"Joe has communicated that through texts, and Torrey [Smith] has told me that they have a session planned and are trying to work out the dates," Harbaugh said at the NFL owners meetings. "I'll be looking forward to seeing how it goes. It is important. It's big."
Flacco knows who he'll be throwing the ball to this year. The Ravens' top three wide receivers -- Torrey Smith, Marlon Brown and Jacoby Jones -- are back along with tight end Dennis Pitta. The only change so far has been the addition of wide receiver Steve Smith.
There was no such familiarity last year, when Flacco lost his top two receivers (wide receiver Anquan Boldin was traded and Pitta was out for 12 games with a hip injury). The biggest adjustment for Flacco is the Ravens' new offensive scheme under coordinator Gary Kubiak. Flacco and the rest of the offensive players have received the playbook, but they can't talk to any coaches about it because of NFL rules limiting players' work in the offseason.
Players are allowed to work out at the Ravens' facility with limited supervision starting April 21.
Pitta said earlier this month that Flacco talked about organizing workouts with his receivers. Flacco is coming off a season in which he threw a career-worst 22 interceptions.
“We were just [a little bit] off,” Flacco said at the end of the season. “If you’re just [a little bit] off and when you’re [a little bit] off throughout the course of the game over the course of 16 games, you’re not going to be special enough to win football games.”