Penn State star Saquon Barkley has been listed as James Franklin’s No. 1 kick returner on the depth chart since the start of training camp. Barkley hasn’t returned a kick for a score yet, but he did take the opening kickoff 37 yards at the start of Penn State’s big win over Georgia State.

In the buildup to the Georgia State game, Franklin compared his star man to Stanford’s Christian McCaffrey, a top-ten draft pick in the NFL who is currently plying his trade with the Carolina Panthers.

“You know – again, I studied this – you look at what Stanford did with their starting tailback [McCaffrey],” Franklin said in his Tuesday press conference prior to Georgia State. “[He] had a huge impact as a tailback, as well as a punt return guy and as a kick return guy.”

During his career at Stanford, McCaffrey returned one kick 98 yards for a touchdown, and was used as the Cardinal’s primary return man in his sophomore year. However, he was used less on special teams in his final year of college ball last season.

This comparison that Franklin made on Tuesday raises an interesting question: how did other running backs fare as their team’s primary kick returner in the NFL?

Darren Sproles

Although Sproles was best known as a productive, pass-catching backup during his 12-season NFL career, he made a huge impact returning kicks for the Chargers, Saints, and Eagles.

Throughout his NFL career, Sproles has returned more than 600 kicks and punts; of those, nine went all the way back for touchdowns. He averaged 25.2 yards per kick return throughout his career, and in the days when touchbacks would place the ball on the 20-yard line, this is a very good number.

One big difference between Barkley and Sproles is that the veteran was never a feature back for his NFL teams, like the Heisman contender is for Penn State. Sproles spent most of his career backing up stars like LaDanian Tomlinson and LeSean McCoy, which gave him room to shine on special teams.

If the Coplay, PA, native can become anywhere near as productive of a returner as Sproles on top of his offensive play, he can become a force to be reckoned with for Penn State and in the NFL.

David Johnson

While David Johnson may have gone first overall in your fantasy draft this year, he probably wasn’t picked that high for his kick return prowess. But before he became one of the NFL’s premier feature backs, he was dynamic in the return game for the Arizona Cardinals.

As a rookie, he returned 22 kicks in five games as the Cardinals’ top returner. His only kick return touchdown was tied for the second-longest play in NFL history: a 108-yard touchdown against the Chicago Bears.

In college, Johnson returned 12 kicks in 14 games for Northern Iowa in his final year of eligibility, scoring one against Iowa. Contrary to what James Franklin does with Barkley, Johnson was used sparingly in the return game in order to keep him on the field as the Panthers’ star tailback.

As Johnson developed into one of the NFL’s best running backs, he was used less in the return game to reduce the star’s risk of injury in the return game.

If Barkley succeeds in returning kicks this season and has a successful NFL career, he’ll probably have a similar career path to Johnson: return a lot of kicks as a rookie, then be weened out of special teams as his role on offense grows.

Jamaal Charles

Before tearing his ACL in 2015, Jamaal Charles was consistently one of the best running backs in football. Before he became a Pro Bowler and an All-Pro, however, Charles used his blazing speed and quickness to return kicks for the Kansas City Chiefs.

While an aging Larry Johnson started at tailback for the Chiefs, Charles was mostly used on special teams. In the 2008 and 2009 seasons, the current Denver Bronco returned 51 kicks for Kansas City, averaging a little more than 24 yards per return. His best return was a 98-yard touchdown against the Pittsburgh Steelers.

Once again, the Chiefs’ coaching staff pulled their star man off of kick return duty once his role on offense was established, but for now, this doesn’t seem to be the plan for Penn State.

As evidenced by three exceptional pro running backs, Saquon Barkley returning kicks and being the focal point of Joe Moorhead’s offense is unprecedented in football. Despite this, James Franklin is confident that this unique move can benefit his team in various ways.

“Saquon Barkley is one of the more explosive players, if not the most explosive player in the country when the ball is in his hands,” he said. “This is a way for us to pretty much guarantee that he’s going to get the ball; or they are going to kick it short to an up-back and we are still going to end up with really good field position.”

Barkley will get another chance to shine in the return game when the Nittany Lions take on Iowa in their conference opener at Kinnick Stadium under the lights.