During the season, he recorded 36 tackles, an interception (which he returned for a touchdown against Indiana), a fumble recovery, and was named to the Big Ten All-Freshman team by The Sporting News.

31, in honor of former Penn State players who had worn the number including All-Americans Shane Conlan and Andre Collins.

He also recorded 12 tackles for loss and three sacks, helping Penn State reach the national top 10 in scoring and total defense.

He won the Big Ten Defensive Player-of-the-Week for his performance against Indiana, making 13 tackles and playing a key role in Penn State's goal-line stand to ensure the win.

[23] He was the fourth linebacker selected in 2007, after future Pro bowlers Patrick Willis, Lawrence Timmons, and Jon Beason.

[24] Throughout training camp, Posluszny competed against veteran John DiGiorgio for the job as the starting middle linebacker after it was left vacant by the departure of London Fletcher.

[25] He made his professional regular season debut and first career start in the Bills' season-opener against the Denver Broncos and recorded ten combined tackles (nine solo) in their 15–14 loss.

[27] On September 23, 2007, Posluszny made four combined tackles before leaving in the third quarter after suffering a broken left forearm in their 38–7 loss at the New England Patriots.

[31] The following week, Posluszny recorded five combined tackles, two pass break ups, and made his first career interception off of quarterback Brett Favre during the Bills' 31–27 loss at the New York Jets.

[32] Posluszny finished the 2008 season with 110 combined tackles (87 solo), six pass deflections, a fumble recovery, and an interception in 16 games and 16 starts.

[36] He started the Bills' season-opener against the New England Patriots and recorded six solo tackles before leaving the 25–24 Monday Night Football loss in the first quarter after breaking a bone in his left forearm.

[42] In Week 13, he recorded five solo tackles and made his first career sack on quarterback Mark Sanchez in the Bills' 16–13 loss to the New York Jets.

[43] On December 20, 2009, Posluszny made nine combined tackles and intercepted Tom Brady for his third pick of the season as the Bills lost to the New England Patriots 17–10.

[51] He unfortunately left the game during the third quarter after sustaining an apparent knee injury while tackling running back Ronnie Brown with two teammates.

[53] On October 31, 2010, Posluszny recorded a season-high 17 combined tackles (11 solo) and broke up a pass during a 13–10 loss at the Kansas City Chiefs.

[54] In Week 13, he collected 15 combined tackles (11 solo) and sacked quarterback Tarvaris Jackson as the Bills were routed by the Minnesota Vikings 38–14.

[58] The tender became null and void, making Posluszny an unrestricted free agent after the signing of the NFL Collective Bargaining Agreement by the NFLPA that ended a four-month lockout.

[64] Head coach Jack Del Rio officially named him the starter along with outside linebackers Daryl Smith and Clint Session.

[69] Posluszny finished the 2011 season with 119 combined tackles (69 solo), a career-high nine pass deflections, two sacks, and two interceptions in 16 games and 16 starts.

[71] Mularkey opted to retain defensive coordinator Mel Tucker with Posluszny, Smith, and Session remaining as the starting linebacker core.

[73] In Week 17, he made ten combined tackles and sacked quarterback Jake Locker twice as the Jaguars lost 38–20 at the Tennessee Titans.

[74] He set a single-season franchise record with 139 combined tackles (106 solo), seven pass deflections, three interceptions, and two sacks in 16 games and 16 starts.

[76] On January 17, 2013, general manager Dave Caldwell announced Seattle Seahawks' defensive coordinator Gus Bradley as the Jaguars' new head coach.

[83] He finished the 2013 season with a career-high 162 combined tackles (122 solo), nine pass deflections, three sacks, two interceptions, and one touchdown in 15 games and 15 starts.

[86] In Week 7, Posluszny tied his season-high of 12 combined tackles and sacked Brian Hoyer during the Jaguars' 24–6 win against the Cleveland Browns.

[103] Posluszny finished the 2016 season with 133 combined tackles (97 solo), a career-high 14 quarterback hurries, three pass deflections, 1.5 sacks, and an interception in 16 games and 16 starts.

[107] In Week 13, Posluszny recorded a season-high 14 combined tackles and made 1.5 sacks on quarterback Jacoby Brissett as the Jaguars defeated the Indianapolis Colts 30–10.

[111] On January 7, 2018, Posluszny started his first career playoff game, but was held without a tackle as the Jaguars defeated the Buffalo Bills in the AFC Wild Card Round.

[112] The following week, Posluszny made three combined tackles and a pass deflection in a 45–42 victory against his home state Pittsburgh Steelers in the Divisional Round.

[115][116] On July 6, 2013, Posluszny married fellow Penn State graduate Elizabeth Sarah Johnson in Pittsburgh, Pennsylvania, before the start of the 2013 regular season.