Denver Broncos star Von Miller is challenging Houston Texans ace J.J. Watt, for NFL Defensive Player of the Year.

Watt has long been considered favourite for the award. However, he should start looking over his shoulder at Miller and four other genuine rivals.

Tim Jennings, CB, Chicago Bears

Diminutive cornerback Tim Jennings is the most prolific thief on the Chicago Bears' opportunistic defense.

The 5'9", 185-pound ball hawk has snared eight interceptions already this season. The 28-year-old has allowed the Bears to vary their coverage schemes.

Jennings can play tight zone and also has the range and quickness to work well in off-man coverage.

If Jennings takes his interception tally to double figures, he could be Defensive POY.

Von Miller, OLB/DE, Denver Broncos

Von Miller is on the verge of becoming the most dominant defensive player in the NFL. The hybrid pass rush ace is a prolific playmaker and the leader of the Denver Broncos' defense.

Miller is allowed to rush from either side of the formation. He operates as both a traditional defensive end from a three-point stance, or as a stand-up rusher.

He's also athletic enough be effective in underneath coverage and blitz the A-gaps. Miller has 10 sacks, just half a sack less than Watt and has also forced two fumbles.

His scheme flexibility and knack for the big play, make Miller a strong contender for Defensive POY.

DeMarcus Ware, OLB, Dallas Cowboys

DeMarcus Ware continues to be the man to fear on the Dallas Cowboys' defense. He is perhaps still the most athletically-skilled pure pass-rusher in the NFL.

Ware has nine sacks this season, 39 total tackles, four forced fumbles and one fumble recovery. The eight-year-veteran is the ideal weapon for maverick coordinator Rob Ryan.

Ware is sent on the blitz from anywhere across the formation. His closing speed is still superior to any defender in the league.

Charles Tillman, CB, Chicago Bears

Bears veteran Charles Tillman is still a turnover machine in his 10th pro season. The 31-year-old has turned forcing takeaways into a fine art form.

Tillman currently has two interceptions, along with a league-leading seven forced fumbles to his credit.

He also has 49 total tackles, 43 being solo stops. That's an impressive number that proves Tillman is still the ideal cover-2 cornerback and an excellent run force defender.

If he continues to binge on turnovers, Tillman has to be considered for Defensive POY.

Sleeper Candidate: Charles Johnson, DE, Carolina Panthers

Superb Carolina Panthers defensive end Charles Johnson can't remain in obscurity much longer. The dynamic 26-year-old has been dominating for the Panthers improving defense this season.

He has 8.5 sacks and more importantly, five forced fumbles. Johnson also has three batted passes and 30 tackles to his credit.

The 6'2" 285-pounder is the ideal 4-3 defensive end. He has the size to hold the edge on the strong side and be a force against the run.

He also has the power, quickness and technique to constantly pressure the pocket.

Not many players on losing teams win this award, so Johnson will have to continue putting up monster numbers.

Hall of Famer Cortez Kennedy should provide inspiration. He was named Defensive POY in 1992, as a member of the 2-14 Seattle Seahawks. So Johnson is still in with a chance.

Watt's performances have been outstanding this season. However, don't be fooled into thinking the race for NFL Defensive POY is over just yet.