Chicago Bears cornerback Bryce Callahan comes off the field after intercepting a Matthew Stafford pass during the Bears win over the Lions Sunday at Soldier Field.
Chicago Bears cornerback Bryce Callahan comes off the field after intercepting a Matthew Stafford pass during the Bears win over the Lions Sunday at Soldier Field. — Mark Busch -

One of the best individual matchups on Sunday's biggest stage in Week 11 pits a pair of former undrafted players from the football factories of Rice and Minnesota State.

Chicago Bears CB Bryce Callahan, the NFL's best nickel corner you probably haven't heard of, if not the best pure nickel, period, vs. Adam Thielen, the NFL's leading receiver, who played D-II ball and earned his spot on Minnesota's 2013 practice squad after impressing as a tryout player at rookie minicamp.

Indeed, with first place in the North on the line Sunday at Soldier Field, where the NFL's highest-paid defensive player will chase its only quarterback with a fully-guaranteed contract, and each star-laden defense boasts no fewer than five former first-rounders, this author's eyes will be fixated on a battle neither Callahan nor Thielen likely imagined as recently as a few years ago.

The secret's already out on Thielen. He was named second-team All-Pro last season, on the heels of signing a four-year, $19.2 million contract with only $9.6 million of it guaranteed — now undoubtedly one of the best bargains in football.

The 6-foot-2, 200-pounder built on that breakthrough by becoming the first player in NFL history with eight consecutive 100-yard receiving games to begin the season. Thielen's 78 catches are tied with the Saints' Michael Thomas, who selected No. 47 overall two years ago from an actual football factory known as Ohio State. Thielen also is only 53 yards shy of his second consecutive 1,000-yard season.

The secret's starting to get out with Callahan, who in his fourth season leads the Bears' superb CB corps in tackles (37), tackles for loss (four, the same number as game-wrecking DL Akiem Hicks) and ranks second with eight pass breakups (two INTs, six PD). Lest we forget to mention, Callahan is 5-9 and 188 pounds dripping wet. The smallest defender on the Bears' roster also might be their toughest pound for pound. Callahan's tenacity is matched with outstanding athleticism and instincts.

Thielen runs roughly 60 percent of his routes from the slot, where his 534 yards — including 199 after the catch — rank second in the NFL, according to ESPN's NFL Matchup. Injuries notwithstanding, Callahan exclusively lines up inside, where he's flanked on the outside by the bigger Kyle Fuller and Prince Amukamara, the pair that will spend a lot of time battling the Vikings' other lethal receiver, Stefon Diggs.

When Callahan lines up across from Thielen, in many ways he'll see firsthand exactly what he's on the cusp of accomplishing. In his contract season, Callahan has played the best football of his life after signing a right-of-first-refusal restricted tender worth $1.9 million last spring. Ironically, among the teams with reported interest in prying Callahan away from Chicago were the Vikings, who otherwise have hoarded premium-round corners under the rein of Mike Zimmer.

Callahan flashed plenty in his first three seasons but missed a combined 16 games because of injuries. The next game Thielen misses in his career will be the first — though now is probably the right time to mention that he was limited in practice Wednesday and Thursday with back and calf issues.

The Bears already have a ton of resources committed in their CB corps ($24 million in Fuller and Amukamara alone in 2019) but could have the good kind of problem on their hands in finding a way to lock up Callahan. Thielen earned his contract extension months after Minnesota spent the 23rd overall pick on fellow WR Laquon Treadwell, and one year before the Vikings would make Diggs one of only eight NFL wideouts promised north of $40 million guaranteed.

Will Callahan continue to force the Bears' hands by being a two-way force in his and the Bears' biggest test to date this season? He admitted following Sunday's game, when he filled the stat sheet with three pass breakups and a sack, that he's locked in right now.

"Yeah, [I'm in the zone]," said Callahan, who showed off his full arsenal of weapons vs. the Lions with textbook coverage on his interception, the hops to out-leap 6-foot-4 Kenny Golladay on a third-down breakup and the blitzing ability to secure the first of Chicago's six sacks of Stafford. "[I'm] trying to have blinders and earmuffs. Just staying focused."

Bears fans and local media already know about the gem GM Ryan Pace unearthed in Callahan. If he replicates his performance in Week 10 vs. Thielen, not even blinders and earmuffs would prevent the rest of the country from catching on.