He spent the last three seasons as an assistant coach at UNI.
Koehler comes to Illinois State, after serving as the offensive coordinator and quarterbacks coach at NCAA Division II Grand Valley State in 2012.
Barnett has been the ISU offensive line coach for the past three seasons.
A share of the Missouri Valley Football Conference title in on the line with a win by the Redbirds.
The Redbirds will play a ranked opponent for the first time in 2012.
The Next Step - Spring Camp - Episode 2
Fall Camp Report: Offensive Line
GoRedbirds.com features a positional breakdown of the offensive line during the 2010 Redbird football fall camp.
Illinois State Football at Eastern Michigan (9/8/12
George Barnett begins his third season on the Redbird coaching staff as the offensive line coach and running game coordinator.
During the 2011 season, the Redbird offensive line was one of the best in the country as they ranked No. 3 in fewest sacks allowed with just six given up all year. The senior-laden group also led the way for a rushing attack that averaged 183 yards per game on the ground, an improvement by over 50 yards per game from the previous season.
For their efforts, senior Cal McCarthy was named a First-Team All-MVFC performer and fellow senior Nick Bledsoe was named to the All-MVFC Second Team. Rounding out the group was senior Cody White, who was tabbed as an All-MVFC Honorable Mention selection.
The Redbird offensive line also helped Ashton Leggett rush for 1,031 yards and 11 touchdowns on the ground, as he became the first ISU back to rush for over 1,000 yards since 2006.
In his first year with the Redbirds, the offensive line unit helped protect Redbird quarterbacks and led the way for an offense that averaged 258.4 yards per game and finished the season ranked 16th in the nation in passing offense.
With an experienced group of lineman that included 2009 All-MVFC second-team selection Bledsoe and 2010 All-MVFC second-team selection McCarthy, the Redbirds recorded the seventh-highest scoring total in school history (321) and team's highest total since scoring 324 in 2007. In addition, running backs Erik Smith (4.6) and Leggett (4.3) each averaged over four yards per carry and Leggett led the team with eight rushing touchdowns.
Barnett came to Illinois State in 2010 following a two-year stint as the offensive line coach at Division II powerhouse Grand Valley State, which advanced to the 2009 NCAA Division II national title game.
The Tuscola, Ill., native thrived in his two seasons at GVSU as offensive line coach and helped the Lakers' offense become one of the best in the country. In 2009, GVSU ranked third in the country in sacks allowed (.60) after giving up just nine sacks in 15 games played. The Lakers also ranked 11th in the country in rushing offense (227.5 ypg), 12th in total offense (450.1 ypg) and 14th in scoring offense (35.8 ppg). Barnett also mentored senior Nick McDonald, who was a consensus Division II All-American and the GLIAC Offensive Lineman of the Year.
In 2008, Barnett guided the GVSU offensive line unit that saw all five of its starters (Sam Allen, Cameron Bradfield, Billy Eisenhardt, Nick McDonald and Jacob Topp) earn All-GLIAC honors. The Lakers finished the season ranked 10th in the nation in scoring (38.5 ppg), 13th in sacks allowed (1.08), 14th in rushing (228.4 ypg) and 25th in total offense (429.0 ypg.
Barnett came to Grand Valley State after a three-year stint as offensive line coach at Indianapolis. The Greyhound offense increased its production every season behind the Barnett-led offensive line. Indianapolis recorded four-year highs offensively in passing yards (234.1 ypg), rushing offense (189.2 ypg) and total offense (423.3 ypg) in 2007.
Prior to his arrival at Indianapolis, Barnett spent the 2004 season at Illinois where he was a graduate assistant and worked with the offensive line for the Illini.
Barnett began his coaching career and taught for five years at Mattoon (Ill.) High School from 1999-2003. He served as assistant head coach for the Green Wave's state semifinalist team in 2003, working as offensive coordinator and the offensive line coach.
Barnett earned a bachelor of science degree in physical education in 1998 from Millikin in Decatur, Ill.
He was a four-year football letterwinner for the Big Blue and earned all-conference plaudits. In addition, he was named to the National Dean's List while at Millikin.
Barnett and his wife, Lori, reside in Bloomington, with their children, Elle and James.