By the numbers – the ones compiled by Pro Football Focus, anyway -– the Detroit Lions' offensive line ranks No. 8 among the 32 teams in the National Football League.
That is a remarkable improvement over the No. 19 ranking Pro Football Focus gave the unit at the end of last season.
In fact, based on a few key stats from last year, some might consider it shocking that the Lions have the eighth best offensive line in the league. After all, the running game ranked last in the league in 2017, and Matthew Stafford was sacked a career-high 47 times.
So why the high ranking? Why have the Lions climbed 11 spots in the Pro Football Focus rankings?
The bottom line: It's how the numbers add up, and expectations for how the rebuilding project has progressed in Bob Quinn's three years as general manager.
Before analyzing the numbers and making comparisons, here are some observations on how the Lions are improved, and where they compare to their NFC North competitors.
View photos of the guards and centers competing for roster spots entering training camp.
Detroit Lions center Wesley Johnson (73) during voluntary offseason workouts at the Detroit Lions training facility on Tuesday, May 8, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Frank Ragnow (77) during rookie minicamp practice at the Detroit Lions training facility on Saturday, May 12, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions guard T.J. Lang (76) during an OTA practice at the Detroit Lions training facility on Thursday, May 24, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions guard Kenny Wiggins during voluntary offseason workouts at the Detroit Lions training facility on Thursday, May 17, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions center Wesley Johnson (73) during an OTA practice at the Detroit Lions training facility on Thursday, May 24, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Frank Ragnow (77) during an OTA practice at the Detroit Lions training facility on Tuesday, May 22, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Graham Glasgow (60) during a minicamp practice at the Detroit Lions training facility on Tuesday, June 5, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Beau Nunn during voluntary offseason workouts at the Detroit Lions training facility on Thursday, May 17, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman John Montelus (64) during a minicamp practice at the Detroit Lions training facility on Tuesday, June 5, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Frank Ragnow (77) during an OTA practice at the Detroit Lions training facility on Monday, June 11, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions guard T.J. Lang (76) during a minicamp practice at the Detroit Lions training facility on Tuesday, June 5, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions center Leo Koloamatangi (75) during an OTA practice at the Detroit Lions training facility on Thursday, May 24, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Beau Nunn (67) during rookie minicamp practice at the Detroit Lions training facility on Friday, May 1, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Graham Glasgow during voluntary offseason workouts at the Detroit Lions training facility on Thursday, May 17, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions guard Joe Dahl (66) during voluntary minicamp practice at the Detroit Lions training facility on Tuesday, April 24, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman John Montelus (64) during rookie minicamp practice at the Detroit Lions training facility on Saturday, May 12, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions guard Kenny Wiggins (79) during an OTA practice at the Detroit Lions training facility on Thursday, May 31, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions center Leo Koloamatangi during voluntary offseason workouts at the Detroit Lions training facility on Thursday, May 17, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Starters: The rankings for the 32 teams are based on the five projected starters for Game 1. That means before teams get hit by injuries, and the Lions were hit hard last year. Injuries forced them to use 10 different starting combinations.
With training camp opening Friday, the Lions are better right now with a healthy starting five than they were even when camp opened last year. They were without left tackle Taylor Decker, who missed all of camp and the first eight games with an injury sustained in the offseason program.
Upgrades: Having Decker back at the start is the biggest one. Drafting Frank Ragnow to play left guard allows Graham Glasgow to open the season at center, his natural position. He played left guard and center his first two years.
North rankings: The Lions' ranking is the highest in the division. The Packers are ninth, Bears 13th and defending division champion Vikings 28th.
Quinn's building project: It has been a three-step, three-year project that should pay off this season. It never ends, but it's in good shape as it stands now.
Step 1 was drafting three offensive linemen in 2016 – Decker in the first round, Glasgow in the third and Joe Dahl in the fifth.
Step 2 was signing two priority free agents in 2017 to be starters – right guard T.J. Lang, who made the Pro Bowl last season, and right tackle Rick Wagner.
Step 3 was drafting Ragnow, the top-ranked center in the 2018 draft, who has the ability – and the college starting experience – to start at guard. His presence locks in place the five-man starting unit.
View photos of the offensive tackles competing for roster spots entering training camp.
Detroit Lions tackle Tyrell Crosby (65) during an minicamp practice at the Detroit Lions training facility on Wednesday, June 6, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Rick Wagner (71) during voluntary minicamp practice at the Detroit Lions training facility on Tuesday, April 24, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Dan Skipper (74) during an OTA practice at the Detroit Lions training facility on Tuesday, May 22, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Tyrell Crosby (65) during rookie minicamp practice at the Detroit Lions training facility on Saturday, May 12, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Corey Robinson (70) during a minicamp practice at the Detroit Lions training facility on Tuesday, June 5, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Rick Wagner (71) during a minicamp practice at the Detroit Lions training facility on Tuesday, June 5, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Brian Mihalik during voluntary offseason workouts at the Detroit Lions training facility on Thursday, May 17, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Tyrell Crosby (65) during a minicamp practice at the Detroit Lions training facility on Tuesday, June 5, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Dan Skipper (74) during an OTA practice at the Detroit Lions training facility on Monday, June 11, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Rick Wagner (71) during an OTA practice at the Detroit Lions training facility on Tuesday, May 22, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Brian Mihalik (72) during an OTA practice at the Detroit Lions training facility on Thursday, May 24, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Adam Bisnowaty (51) during a minicamp practice at the Detroit Lions training facility on Tuesday, June 5, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Corey Robinson (70) during an OTA practice at the Detroit Lions training facility on Thursday, June 14, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Dan Skipper (74) during an OTA practice at the Detroit Lions training facility on Tuesday, May 22, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions offensive lineman Tyrell Crosby (65) during an OTA practice at the Detroit Lions training facility on Thursday, May 24, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Detroit Lions tackle Brian Mihalik (72) during an OTA practice at the Detroit Lions training facility on Thursday, May 31, 2018 in Allen Park, Mich. (Detroit Lions via AP)
Here is a look at the Pro Football Focus rankings for the Lions' starting five:
Left tackle, Taylor Decker: His rating of 60.5 for an abbreviated season put him 46th among all tackles in 2017. It was down from his 80.7 ranking as a rookie in 2016, when he started all 16 games and played every offensive snap.
There was a significant drop in performance at left tackle with Decker unavailable for the first half of last season.
By comparison, Greg Robinson had a 36.6 rating for the first six games he started as Decker's replacement. That put him 78th among all tackles.
Left guard, Frank Ragnow: His 93.7 college ranking is second highest of 10 rookie offensive linemen who are projected as starters by Pro Football Focus. Only Colts guard Quenton Nelson's 95.1 ranking is higher.
Center, Graham Glasgow: Pro Football Focus ranks Glasgow as a guard, with a 76.2 ranking. He started 11 games at left guard last year and five at center. He moved over when Travis Swanson missed five starts at center because of injuries.
Swanson was not brought back by the Lions. He signed with the Jets, where he is projected as a backup at center and guard.
Glasgow ranked No. 21 among guards. Swanson's 43.1 ranking made him No. 32 among centers. The rankings indicate a substantial player-for-player upgrade for the Lions.
Right guard, T.J. Lang: A 79.1 overall ranking put him 13th among guards. He played in his first Pro Bowl, moving up as an alternate. An injury prevented him from playing in the Pro Bowl the previous year as a member of the Packers.
Right tackle, Rick Wagner: An 81.9 ranking was 11th among all tackles and the highest for the Lions' offensive linemen.
