Morgan Burnett was drafted high, anointed as an immediate starter and then paid handsomely four months ago to be the fourth exceptional safety for the Green Bay Packers in the last two decades.

That hasn't happened yet for Burnett, and now well into his fourth season there are doubts it ever will.

Burnett certainly isn't a bad player. He provides a measure of functionality almost equally against both run and pass. He's a worker bee. His athletic ability and speed are more than adequate. He has ideal size. And he can direct a secondary at a satisfactory level.

Burnett just isn't an impact player, which is what general manager Ted Thompson was hoping for in 2010 when he traded up to select him in the third round.

"He's a middle-of-the-road, average NFL starting safety," an AFC personnel director said last week. "There are no dominant traits. He won't be a difference-maker, but he isn't going to hurt you, either."

Several years ago, STATS created a statistical measure to rate the big-play performance of defensive backs. They combined a player's interceptions, forced fumbles, passes defensed and sacks, and coined the total as "ballhawks."

In 2011, when Burnett played 98.5% of the Packers' defensive snaps, he had 14 "ballhawks" to rank tied for 35th among all defensive backs.

Last year, Burnett played 100% of the snaps and totaled nine to tie for 77th in "ballhawks."

Having played in just seven of the 10 games this season but still 77.3% of the snaps, Burnett has three "ballhawks" and is tied for 145th. Counting just safeties, he's tied for 54th.

He has two interceptions in his last 25 games, both on the same Sunday last December against Christian Ponder of the Minnesota Vikings.

Of his four career forced fumbles, the last one came 11 games ago.

In terms of "ballhawks" per snap, Burnett has gone from one every 77.2 in 2011 to one every 120.9 in 2012 to one every 152 this year.

Defensive coordinator Dom Capers and safeties coach Darren Perry have defended Burnett countless times, citing circumstances and roles, opportunities and good fortune.

Each knows that defensive football, now more than ever, hinges on the ability to take the ball away. And Burnett, in a primary takeaway position, simply hasn't done it.

The Packers have been down this road three times before during their football renaissance. While Burnett's fourth season has been filled with mediocrity, that fourth season was the absolute break-out point for three of the half-dozen finest safeties in franchise history: LeRoy Butler, Darren Sharper and Nick Collins.

Butler, a second-round draft choice in 1990, played cornerback for two years before moving to safety. After feeling his way for a year, he made the all-pro team in 1993 with seven interceptions, 24 passes defensed and seven tackles for loss in 18 games.

"I'm telling you, confidence is everything," Butler once said. "Once you get the confidence I used to have ... it didn't matter what was going on, I could make it work. I felt like nobody could throw on me or could run on me."

A total team player and encompassing leader, Butler had an amazing knack for knowing precisely when to take a chance. In short, he could pull the trigger.

Sharper was drafted in the second round in 1997. A successful back-up cornerback as a rookie, he moved into the lineup opposite Butler in '98.

For two seasons, Sharper was almost a complete liability. Not only did he not find the football, he was constantly out of position, missed a ton of tackles and wasn't playing to his keen intelligence.

In 2000, his fourth season, Sharper became a Pro Bowl starter with an NFL-high nine interceptions, 23 passes defensed (10 more than he had in his first three seasons combined) and a score of punishing hits.

A second-round pick in 2005 and an instant starter, Collins basically never made a big play in his first three years. He did have four interceptions but dropped another eight. With Aaron Rouse waiting in the wings, 2008 was Collins' last chance to show.

Show Collins did, earning the Pro Bowl start by returning his seven interceptions for 295 yards and three touchdowns. He harnessed his remarkable speed and athleticism, began trusting what he saw and started catching the ball for a change.

The careers of Butler (12 years) and Collins (seven) were cut short by injury, and Sharper was out after 14 seasons.