Smith has become the integral part of the Ravens' passing game following the departure of Anquan Boldin in the off-season and has so far caught 27 passes for 556 yards and one touchdown in the 2013 campaign.
"I think toward the last quarter of the season last year, last half of the season -- he's become a guy that you can throw the ball to, and you know he's going to come down with the ball," Flacco told ESPN.
"You look at before that, he had the ability to make all kinds of plays, and he would make a lot of plays, but he'd put the ball on the ground here and there.
"Sometime last year, he became that guy that caught really everything you threw to him, and I think he's becoming more and more of that guy."
The Ravens face the Green Bay Packers in the NFL later today.