Since Crennel is a former defensive coordinator for the team, one could assume that a good portion of these players that would be the most excited would come from that side of the ball.
Here are seven Chiefs that should be the most thrilled about Romeo's return to the Chiefs in 2012.
Like his former college teammate Glenn Dorsey, Tyson Jackson made great strides for the KC defensive line in the 2011 season.
He finished with 55 tackles and a sack, as his improved play helped linebackers Derrick Johnson and Tamba Hali have big seasons.
At just 25 years old, Jackson is the youngest member of the Chiefs D-line, and still has the most room to grow as well.
With one of the best defensive minds returning to coach him next season, he has to be very excited for his future with the team.
Dorsey has steadily improved in each of his four seasons in Kansas City.
Along with teammate Tyson Jackson, Dorsey was among tops in the NFL in 3-4 defensive end stops last season, with 61 on the year.
There is no question that his defensive coordinator Romeo Crennel had something to do with that.
Although Dorsey might still be undersized for a 3-4 DE, Crennel has been able to make it work for him in KC for the past couple seasons.
Chiefs safety Kendrick Lewis was arguably their most improved defensive player this past season.
He had 60 tackles, 10 pass deflections and three interceptions for one of the best secondaries in the league.
Some of this has to be attributed to Romeo Crennel defensive mind and game-planning.
Lewis should be elated he will get to learn and improve even more in his new head coach's defensive system.
Even though star safety Eric Berry missed nearly the entire 2011 season, he still has a lot to look forward to next season.
He will rejoin a defense that is on the rise and performed well without him this past season.
It's a good bet that Berry will also be used in a variety of ways week to week.
Crennel's familiarity with Berry will really go a long way with this defense in the future.
Derrick Johnson has quietly become one of the best inside linebackers in the game.
He has led the team in tackles in each of the past two seasons and earned his first Pro Bowl trip of his career this year.
Romeo Crennel's 3-4 defensive system has worked wonders for Johnson, who was a backup ILB for KC much of the '09 season.
With Crennel still with the team, I expect Johnson to get better and better each year in helping this Chiefs defense become one of the best units in the league in the near future.
Houston was the ROY for the Chiefs in 2011.
After a slow start to the season, he came on strong in the second half of the campaign, recording 5.5 sacks in the final five games of the year.
After a full year of experience under Crennel, I look for him to have a big 2012.
He should continue flourishing as a pass-rushing threat opposite Tamba Hali.
Tamba Hali has to be the most excited out of anyone on the current Chiefs roster for Romeo Crennel's return.
Crennel has helped Hali revive his career as a starting OLB for Kansas City.
Since making the transition to a 3-4 outside linebacker just three years ago, the former Penn State star has racked up 34.5 sacks during that time, including an AFC-leading 14.5 in the 2010 season.
Hali was also one of the only Chiefs defensive players to publicly endorse Crennel for head coach.