Ryan Wood

USA TODAY NETWORK-Wisconsin

Last in a four-part NFL draft data series.

GREEN BAY - For any general manager, drafting David Bakhtiari in the fourth round would be a pick worth remembering.

Since Ted Thompson was hired by the Green Bay Packers in 2005, 175 college offensive tackles were drafted after the first two rounds. Bakhtiari, a fourth-round pick in 2013, is the only left tackle from the group selected to the Associated Press first or second All-Pro team.

In NFL draft terms, Bakhtiari is a winning lottery ticket.

PART ONE: Packers' first-round focus on defense fails to deliver

PART TWO: Rating Ted Thompson's hits with compensatory picks

PART THREE: Putting Thompson's draft fortunes on the line

Yet against the backdrop of recent Packers drafts, Bakhtiari stands out for another reason. He is one of two All-Pro players Thompson drafted in the past seven years, along with 2014 first-round safety Ha Ha Clinton-Dix. It’s staggeringly few for a general manager who found high-impact talent on an almost-annual basis early in his tenure.

With a four-year, $48 million extension before the 2016 season, Bakhtiari is the rare Thompson draft pick in recent years to receive a second contract from the Packers. Of the 21 players the Packers drafted in 2011, '12 and '13, only five remain on the roster.

Bakhtiari is the only 2013 draft pick still with the team. Of the five who reached the end of their rookie contract, four signed free-agent deals with other teams this spring.

“The reality,” Packers President/CEO Mark Murphy said at the NFL meetings, “is you can’t pay everybody. It’s a hard cap, so you have to work within it. And, you know, each case is kind of unique. Obviously, disappointed to lose some of the players that we did this year, but … you have to look at each player and what are you comfortable paying.

“There’s certain players that other teams were willing to pay more than we thought was reasonable.”

With so many drafted players departing, it’s no surprise Thompson dipped more into free agency this spring than any time in the past decade. The Packers signed four free agents from other teams: tight ends Martellus Bennett and Lance Kendricks, defensive tackle Ricky Jean Francois and cornerback Davon House. It’s the most outside free agents Thompson has signed since 2006.

Bennett was the first unrestricted free agent Thompson signed in five years, ending the NFL’s longest drought.

Thompson changed his approach this offseason out of necessity. The Packers' recent lack of draft production is enough to wonder whether Thompson, among the NFL’s best evaluators of college talent, has hit a draft slump.

PDF: Comparing Ted Thompson to other GMs

RELATED: Complete Packers draft coverage

PDF: Ted Thompson's draft picks by position

McGINN: Rating 2017 top NFL draft prospects

To help determine whether the Packers' slip in draft production signifies a slump, USA TODAY NETWORK-Wisconsin conducted a study comparing Thompson to his contemporaries. Four Super Bowl-winning general managers have overseen their team’s draft longer than a decade: Thompson, the Baltimore Ravens’ Ozzie Newsome, the New England Patriots’ Bill Belichick and the Pittsburgh Steelers’ Kevin Colbert.

The study compared Thompson to some of the NFL’s top talent evaluators, befitting someone with his history. Research examined each general manager’s track record acquiring All-Pro and Pro Bowl talent, as well as retention of draft picks throughout their tenure.

It showed Thompson’s most recent draft classes haven’t matched the retention or talent found in his first five years.

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Retention is perhaps the most important element to Thompson’s draft-and-develop formula.

A high allotment of players under rookie contracts helps teams manage their salary cap. In a sport that values youth, it also keeps the roster young and growing together within a singular scheme.

Since 2005, Thompson’s 44.4 percent retention of drafted players for four seasons — the collectively bargained length of rookie contracts — is roughly 10 percent higher than the NFL average, according to USA TODAY NETWORK-Wisconsin data. It’s also higher than the retention rate of the Patriots (29.7 percent), Steelers (41) and Ravens (43.5).

The Packers' four-year retention of players drafted in 2011, '12 and '13 stayed almost the same, dipping only to 42.8 percent (9 of 21). But the Packers retained fewer players from those three drafts than the Patriots’ 10 (43.4 percent), Steelers’ 12 (48 percent) and Ravens’ 12 (46.1 percent).

Thompson retained six more drafted players (23 total) in his first five years than in his next seven. He also signed one more drafted player (20 total) to a second contract in his first five years than in his next seven. He is the only general manager among the four to retain and re-sign more players in his first five years than in the next seven.

The Packers' recent first-round picks follow the same pattern. Of Thompson’s five initial first-round picks, four started at least 78 games. B.J. Raji might have made it four first-round picks starting at least 100 games if not for early retirement.

Since 2010, Thompson’s first-round picks have been hit-and-miss. Right tackle Bryan Bulaga and outside linebacker Nick Perry developed into centerpieces on the roster. Offensive tackle Derek Sherrod failed to see the end of his rookie contract, and edge rusher Datone Jones wasn’t re-signed.

Clinton-Dix, the Packers' 2014 first-round pick, made a Pro Bowl and second-team All-Pro last season and appears to be a long-time centerpiece for the team. It’s too early to know how 2015 first-round cornerback Damarious Randall and 2016 first-round defensive tackle Kenny Clark develop, though Randall struggled in his second season.

Thompson leaned on free agency this spring to replace the drafted players he was unable to retain. He signed House, a 2011 fourth-round pick, to replace the departed Micah Hyde. Jean Francois fills the void Jones left when he signed with Minnesota. A replacement for Eddie Lacy likely will come through the draft.

Free agency is a necessary way to fill roster holes. The last Super Bowl champion that didn’t sign an unrestricted free agent within five years of winning the title was the 1993 Dallas Cowboys. The NFL’s unrestricted free-agency model started the same year.

Yet the draft remains the ideal method for building a team. Finding impact talent through the draft is the best way to create a contender.

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In a competitive league where job security is fleeting, long careers depend on drafting talented players immediately. Chances are a general manager’s first five years will be his best.

In his first draft, Belichick selected quarterback Tom Brady in the sixth round. In his second draft, Newsome’s first two picks netted Hall of Famers Ray Lewis and Jonathan Ogden. Colbert drafted safety Troy Polamalu in his fourth draft and quarterback Ben Roethlisberger in his fifth, another pair of likely Hall of Famers.

Thompson arguably had a better first five years than any of them.

With his first pick in 2005, Thompson drafted future Hall of Fame quarterback Aaron Rodgers. With his second, he drafted three-time All-Pro safety Nick Collins, a potential Hall of Famer if not for a 2011 neck injury that prematurely ended his career.

But Thompson’s early success stretched beyond his first two picks. In four of his first five drafts, Thompson selected at least one Pro Bowler: Rodgers and Collins in 2005, Greg Jennings in 2006, Jordy Nelson and Josh Sitton in 2008, and Raji, Clay Matthews and T.J. Lang in 2009.

Thompson’s hot streak was slightly better than his peers. In his first five years, Thompson’s seven drafted Pro Bowlers put him ahead of Belichick (six), Newsome (five) and Colbert (five). His five All-Pro players tied Newsome for second, behind Belichick’s six and ahead of Colbert’s three.

That Thompson was unable to continue his torrid streak isn’t surprising. His peers were unable to match their annual rate of finding Pro Bowlers and All-Pros.

Of the four, Thompson’s rate dropped the most.

Thompson drafted three Pro Bowl players in the past seven years: receiver Randall Cobb, running back Eddie Lacy and Clinton-Dix. It’s the fewest among the four Super Bowl-winning general managers. Belichick and Colbert drafted seven Pro Bowlers apiece between their sixth and 12th draft classes.

The gap between Thompson and his contemporaries is wider with drafted All-Pro players.

Thompson’s two drafted All-Pros in the past seven years rank fourth among the group, behind Newsome (six), Belichick (six) and Colbert (four). Newsome's All-Pro players received 18 first- and second-team selections; Belichick's received 17. Colbert’s four All-Pros between his sixth and 12th draft classes totaled 11 selections.

It’s hard to say why Thompson’s recent drafts haven’t matched the same production from his first five years. One possibility is key departures in the Packers' front office.

After the Packers drafted Pro Bowlers with their first three picks in 2009, director of football operations John Schneider was hired as the Seattle Seahawks general manager. John Dorsey was hired as the Kansas City Chiefs general manager before the 2013 season. Schneider and Dorsey are talented personnel evaluators. Both have had success in the draft with their new teams, though Schneider doesn’t have final say in the Seahawks’ personnel matters.

There’s no way to know how much Schneider and Dorsey influenced Thompson’s draft decisions in the past. Those decisions have always been Thompson’s to make.

More likely, Thompson’s slump highlights how difficult it is to find continuous success in the draft. For even the best talent evaluators, guesswork is part of the process. No one knows how a college player will transition to the NFL, until he does.

Perhaps it also means Thompson is due for a big return entering next week’s draft. That’s the thing about slumps.

Eventually, most of them end.