BALTIMORE -- The Baltimore Ravens have a reputation for being the best at punt returns, regardless of who is fielding them.

Over the past three seasons, seven players have returned punts for the Ravens, and Baltimore leads the NFL with a 11.7-yard average. This shows the team knows how to find returners and plug them into its system.

But the Ravens have had a problem this summer that can derail their special teams success.

"We have to find a punt returner that can catch the ball," Ravens coach John Harbaugh said. "And I think we knew that."

In Thursday's preseason opener, punt returners Keenan Reynolds and Kaelin Clay both dropped punts, although Reynolds' mistake didn't officially count because the Panthers were flagged for interference.

This has been a recurring problem throughout training camp. The Ravens have tried to help their returners secure the ball better with different drills. Returners have held three footballs while trying to field punts, and they've had to throw a ball in the air before the punt comes and must catch both of them.

Michael Campanaro has been the most sure-handed returner, but he can't stay healthy. He missed the offseason with a calf injury and has yet to participate in back-to-back training camp practices.

The Ravens have been high on Reynolds, a sixth-round pick who is making the switch from college quarterback. But the rocky transition continued Thursday when he dropped another punt, but that was negated by a Carolina penalty.

"Keenan is a work in progress," Harbaugh said. "I think he’ll learn fast -- we’re not going to give up on him. So we’ll just keep working with him. It was his first time under the lights, and guys were buzzing all around him, but that’s a catch he needs to make."

Clay is one of the seven players to return punts for the Ravens since 2013, joining the productive group of Campanaro, Jacoby Jones, Tandon Doss, Jeremy Ross, Lardarius Webb and Steve Smith Sr.

Last season, Clay returned a punt 82 yards for a touchdown on "Monday Night Football" against the Browns. But his inability to field a punt led to a 36-yard field goal for the Panthers.

"Kaelin Clay can catch the ball," Harbaugh said. "He’s proven that in games, so I was really surprised by that one."

One intriguing option in free agency is Devin Hester, who was released last month by the Atlanta Falcons. Hester holds NFL career records with 20 return touchdowns and 14 punt return scores.

But Hester, 33, won't sign with another team until his surgically repaired toe is back to normal. He estimated last month that he's at 75 percent to 80 percent healthy after having an operation in January to repair a broken sesamoid bone in his right big toe.