No, he isn't attempting to come back as a player. Rather, he will be a member of the coaching staff of the Seattle Seahawks under his former college head coach Pete Carroll. Udeze will work with the Seahawks' defensive line.
Udeze, the 20th overall pick of the 2004 NFL Draft, played in 51 games for the Vikings over his career, starting in 47 of them. He recorded 117 tackles and 11 sacks for the team during that time. He was diagnosed with acute lymphoblastic leukemia in 2008, and was placed on injured reserve for that season as he battled the disease. After the leukemia went into remission, he attempted a comeback with the Vikings, but just never regained the strength he had prior to his cancer treatments. On July 20, 2009, he officially announced his retirement.
In the interim, he has gone back to USC to finish his degree in sociology, as well as working for the University of Washington as an assistant strength coach and a defensive line assistant.
Congratulations to Kenechi Udeze on making his way back to the big stage, and hopefully he will have continued success in Seattle.