Potential replacements for Giants' defensive coordinator Perry Fewell

[UPDATE: 7:18 P.M. ET]

Hearing it is "50-50" that Fewell returns. Or is it "50-50" he is fired? Damn, I forgot to ask. Anyway, Giants still in process of deciding.

— Tom Rock (@TomRock_Newsday) December 30, 2014

Tom Coughlin is coming back in 2015 to coach the New York Giants for a 12th season. That, however, doesn't mean he will get his wish that his coaching staff returns intact. Coughlin and co-owner John Mara are reportedly meeting Monday afternoon, and the main topic of conversation will have to be the coaching staff, especially the future of embattled defensive coordinator Perry Fewell.

We have already made the case for replacing Fewell. Bottom line is the Giants have, for whatever reason, given up too many points during Fewell's five seasons.

2014: Yards per game, 375.8 (29th); Points per game, 25.0 (23rd)

2013: Yards, 332.2 (8th); Points, 23.9 (18th)

2012: Yards, 383.4 (31st); Points, 21.5 (12th)

2011: Yards, 367.6 (22nd); Points, 23.1 (21st)

2010: Yards, 310.6 (7th); Points, 24.4 (21st)

Let's not rehash that argument. Instead, let's discuss potential replacements if the Giants do decide to move on.

The Leading Candidates

Steve Spagnuolo

Spagnuolo was, of course, the architect of the aggressive defense that helped the Giants win the 2007 Super Bowl. When potential successors to Fewell are discussed, his name is always at the top of the list. Whether a return to New York by Spagnuolo is realistic, or smart, is something that the organization will have to look into.

We discussed a potential return here several weeks ago. Much has happened with Spagnuolo since he left the Giants after the 2008 season. We laid out both the pros and cons of bringing Spagnuolo, currently coaching defensive backs for the Baltimore Ravens, back to the Giants. Spagnuolo is no longer one of the hot young coaching prospects in the league as there have been some black marks against him since his time with the Giants. Here is part of what I wrote:

It can't simply be assumed that a Spagnuolo who would come back to the Giants in 2015 is the same one who left after 2008. The entire situation would need to be fully vetted, including his current work with the Ravens.

At the very least, if Fewell is fired Spagnuolo will be part of the conversation when it comes to a replacement.

Pepper Johnson

The former New York Giants linebacker just completed his first season coaching the defensive line for the Buffalo Bills after 13 seasons with the New England Patriots, where he coached the linebackers and defensive line at different times. Now 50, Johnson made it clear when he left the Patriots that he was doing so in order to put himself in position to eventually become a defensive coordinator. He told BuffaloBills.com that becoming a defensive coordinator was "a dream of mine and a goal of mine."

NFL.com Bills beat writer Chris Trapasso recently told me that Johnson has done a "great job" with the Buffalo defensive line.

"You'd think he'd be a good DC candidate because he's been in NE and has coached LBs and DL now," Trapasso said. "And he obviously has experience running multiple fronts. Also, Bills backup DTs and DEs have been very good this year too under Johnson."

There are a couple of factors that might work against the hiring of Johnson, if the defensive coordinator job is available. First is the fact that Tom Coughlin's time is probably running short. He could well be one more year and done with the Giants. Back in 2007 Coughlin gambled by hiring a relative unknown in Spagnuolo to lead the defense. That, of course, turned out to be a brilliant move. Last year Coughlin handed the offense to a first-year coordinator. Would he be willing to do it again?

The other nagging question is why did Johnson, who both played and coached for Bill Belichick, have to leave the Patriots to seek a promotion? Johnson was a defensive assistant in New England for 13 years, and was consistently passed over for the coordinator job. To give him the job in New York, you have to think the Giants need a satisfactory answer to that question.

Other Names To Discuss

Rex Ryan is, of course, unemployed after being fired Monday morning as head coach of the New York Jets. Ryan is a tremendous defensive coordinator and there is a romantic notion that teaming Ryan with Coughlin would fix the Giants' defense and be sort of cool at the same time. Only it isn't going to happen.

Ryan has reportedly said he would rather work in television that return to being a coordinator. So, it's head coach or bust for him. Besides, do you really think Ryan would take a coordinator job for a team in the same stadium where he just spent six years as a head coach?

Jim Harbaugh just left the San Francisco 49ers, almost certainly to become head coach at the University of Michigan. That means that highly-respected 49ers defensive coordinator Vic Fangio is looking for work. Some te think the 56-year-old Fangio could be in line for a head-coaching job. If he doesn't, perhaps his name should be in the mix. He's been a top-notch coordinator for a long time.

The Atlanta Falcons fired head coach Mike Smith on Monday, making another veteran defensive coordinator the Giants are familiar with -- Mike Nolan -- available. Nolan was Giants' defensive coordinator way back in 1993, when he was only 33 years old. He has been a defensive coordinator in Atlanta, Miami, Denver and Baltimore. He also did a stint as head coach of the Broncos.

Feel free to add your names. I am sure there are guys I discounted or didn't think of who would be valid additions to the list.