As we get ready for the flag to drop on free agency, it seems like Case Keenum is flying under the radar. He ended last season with a thud in the NFC championship game in Philadelphia, but he had a great season. He takes care of the ball and was able to move Minnesota’s offense.

Keenum was particularly good during the second half of the regular season, completing 71 percent of his passes, with 15 touchdowns versus 4 interceptions. Using the NFL’s complex “passer rating” system, he was the league’s leading passer during the second half of the season (the final eight games for each team), clocking in at 107.2.

Specifically, why are we hearing a bunch of chatter about where AJ McCarron might land? Seems like as well as Keenum played last year, he should be earning a lot more than McCarron. Relative to what he’ll be paid, he might end up being a much better deal also than Kirk Cousins.

Overall, 28 quarterbacks attempted at least 100 passes in both the first half of the season and the second half of the year. (That’s looking at the first eight games for each team and the last eight games.) Of that group, Keenum was the 2nd-most improved (using passer rating). And that’s not to imply that he wasn’t any good early in the year. In his first eight games, he completed 64 percent of his passes, with 7 TDs and 3 interceptions (in six starts).

Ben Roethlisberger was the league’s most improved passer last year, with his passer rating climbing from 82.7 to 103.6 when comparing the two halves of the season. Also up there was DeShone Kizer, who improved from being god-awful to just lousy.

On the improvement front, Joe Flacco is the other name that pops. He was remarkably bad during the first half of the year, but he was a lot more productive in his final eight game, with 6 more touchdowns, 3 fewer interceptions and 561 more passing yards.

Among the big decliners, Dak Prescott led the way, followed by the two principal figures in the first big move of the offseason (Alex Smith and Kirk Cousins).

Here are the numbers for those 28 who attempted at least 100 passes in both the first of the season and the second half. For each guy (and in each eight-game chunk) you’re looking at completion percentage, passing yards, touchdown passes and interceptions. The final column shows the improvement of each player’s passer rating.

MOST IMPROVED PASSERS (2nd half of season)
Player1st (Pct-Yds-TD-Int)2nd (Pct-Yds-TD-Int)Rating
Ben Roethlisberger61%-2062-10-967%-2189-18-5+20.9
Case Keenum64%-1610-7-371%-1937-15-4+18.4
DeShone Kizer52%-1144-3-1155%-1750-8-11+17.0
Philip Rivers61%-2028-13-665%-2487-15-4+14.9
Joe Flacco64%-1290-6-864%-1851-12-5+14.3
Jameis Winston61%-1920-10-667%-1584-9-5+11.8
Matthew Stafford62%-2212-14-470%-2234-15-6+10.6
C.J. Beathard53%-647-2-357%-783-2-3+7.8
Jared Goff60%-2030-13-464%-1774-15-3+5.2
Cam Newton63%-1841-10-1155%-1461-12-5+3.4
Jacoby Brissett60%-1642-5-457%-1456-8-3+1.5
Carson Wentz60%-2063-19-559%-1233-14-2+0.6
Andy Dalton63%-1739-11-857%-1581-14-4+0.2
Russell Wilson62%-2305-17-660%-1678-17-5-1.1
Josh McCown71%-1840-12-762%-1086-6-2-2.1
Drew Brees72%-2214-13-472%-2120-10-4-2.3
Matt Ryan66%-2157-11-764%-1938-9-5-2.9
Blake Bortles59%-1657-10-561%-2030-11-8-3.1
Tom Brady67%-2541-16-266%-2036-16-6-7.9
Derek Carr64%-1654-12-661%-1842-10-7-8.4
Eli Manning63%-1820-12-660%-1648-7-7-10.4
Marcus Mariota63%-1519-6-561%-1713-7-10-11.1
Trevor Siemian61%-1669-9-1053%-616-3-4-11.9
Jay Cutler66%-1306-10-558%-1360-9-9-13.6
Tyrod Taylor65%-1628-10-259%-1171-4-2-15.1
Kirk Cousins68%-2147-13-461%-1946-14-9-16.1
Alex Smith69%-2181-16-066%-1861-10-5-21.8
Dak Prescott63%-1818-16-463%-1506-6-9-23.9

—Ian Allan