When trying to project how first-round pick Anthony Barr will fare during his rookie season, you may want to point to what Aldon Smith and Von Miller did as rookies as the best-case scenario.

The reality is, though, that it takes most edge rushers time to find their groove at the next level.

While Smith had 14 sacks for the 49ers in his first season in 2011 and Miller was not far behind with 11.5 for the Broncos, edge rushers racking up double-digit sacks as rookies is not common.

For every Smith and Miller, there is a Vernon Gholston or Aaron Maybin who made little impact.

Looking at the 32 edge rushers selected in the previous seven drafts, those players averaged just 3.7 sacks and 20.2 tackles as rookies despite playing 509 snaps on average in their first season, according to Jeff McLane, who did some digging on rookie pass rushers for the Philly Inquirer.

Gholston and Maybin were top picks of the Jets and Bills, respectively, who did not record a sack as rookies. Gholston is the worst-case scenario, having washed out of the league without a single sack.

The Vikings, of course, are confident Barr will develop into a star pass rusher. General manager Rick Spielman has said that they projected the outside linebacker out of UCLA as the second-best pass-rushing prospect of this class behind Texans outside linebacker Jadeveon Clowney.

While it appears that Barr will be facing an even steeper learning curve than his rookie peers and predecessors considering he didn't start playing defense at UCLA until his junior year, the Vikings said that Barr, before he got sent back to California, did not look like a major project.

"I know that's a big thing with everybody that he's only played two years, but the things he's done defensively he's done pretty well," coach Mike Zimmer, who envisions Barr playing a hybrid role like Miller does in Denver, said two weeks ago. "I don't think it's going to be an issue whatsoever."

Still, while the Vikings anticipate that Barr will ascend to a starting role by the time training camp ends, it might be best to curb your enthusiasm when it comes to his first-year sack total. Potent rookie pass rushers like Smith, Miller, Brian Orakpo (11 sacks for the Redskins in 2009) and Clay Matthews III (10 sacks for the Packers in 2009) appear to be exceptions to the rule.

"Everybody has a development stage," Spielman, speaking generally about the immediate contributions of rookies, said last month. "Some hit it right off the bat. Some take some time."