Kenseth is leaving Roush at the end of the season to take over the No. 20 at Joe Gibbs Racing.
"We are excited about this change on both fronts," Jack Roush said in a release. "Pairing two highly successful veterans like Carl and Jimmy should be quite a matchup and it is our expectation based on what Jimmy has been able to accomplish with many high profile drivers, that it will provide the spark to get the No. 99 program and Carl back into championship form."
Edwards' long-time crew chief Bob Osborne stepped down in July for health reasons and was replaced by Chad Norris. However, the switch didn't boost Edwards' performance, and he missed the Chase and is currently in 15th place in the points standings without a win. Edwards, who lost out on the 2011 championship to Tony Stewart by virtue of fewer wins, has three top five finishes in 2012 compared to 19 a year ago. It's the second time in eight full seasons that he's missed the Chase. Kenseth is currently sixth in the Sprint Cup Series points standings, and won the Daytona 500 in February.
Fennig and Kenseth have been together since the middle of the 2010 season and have won three races each in 2011 and 2012. Fennig, a long-time Roush employee, won the 2004 Sprint Cup Series title with Kurt Busch. His move from atop the No. 17 box means that team will have both a new driver and crew chief in 2013.
Potentially two-time Nationwide Series champion Ricky Stenhouse is moving up to the Cup Series full-time in 2013, and will have Scott Graves has his crew chief. Graves was the crew chief for Edwards' Nationwide Series win at Watkins Glen earlier in the year and has conducted testing with the new 2013 Sprint Cup Series car.