Mark Dantonio's retirement can't be that much of a surprise. Embroiled in a wrongful termination lawsuit, Coach D merely had to get past Jan. 15 when he collected a $4.3 million retention bonus.

Lately, Dantonio had been criticized not only for the downturn of the football program but off-the-field issues as well. There have been questions about some of the players he has brought into the program over the last few years beyond the three dismissals in 2017.

Still, on the field, we will remember the Dantonio era fondly at MSU. He took over the Spartans in 2007 about the time Michigan's Mike Hart was calling Michigan State "Little Brother." A blood feud took off from there. Dantonio went 8-5 against the Wolverines.

That was part of Dantonio becoming the winningest coach in school history. He won 114 games, three Big Ten titles and took the Spartans to the 2015 College Football Playoff. That came a year after Dantonio led Michigan State to its first Rose Bowl in 26 years, a 24-20 win over Stanford. At that point, Michigan State hadn't been as powerful and relevant since the 1960s under Duffy Daugherty.

Coach D will be known for his sheer grit. He took three-stars and coached them up to play like five-stars. His Spartans played with a similar determination.

A day before the formal National Signing Day commences, Michigan State becomes the sixth opening since the 2019 early signing period.

Here are the top candidates to replace Dantonio at Michigan State.

Luke Fickell, Cincinnati coach: Fickell is the leader in the clubhouse until further notice. He and Dantonio coached under Jim Tressel at Ohio State for two years, winning a national championship together in 2002. Fickell now has proven himself as a head coach after posting back to back 11-win seasons at Cincinnati. Most of all for Michigan State, Fickell is Big Ten born and bred having played linebacker at Ohio State and recruiting the region for most of his career.

Pat Narduzzi, Pittsburgh coach: Another no-brainer for Michigan State fans who remember Narduzzi as Dantonio's defensive coordinator from 2007-14. While Narduzzi's results have been mixed at Pittsburgh (36-29), knowing the culture and recruiting at Michigan State would be a huge plus. From 2011-14, Narduzzi's Michigan State defense was the only FBS unit to finish in the top 10 in total defense and rushing defense. At Pittsburgh, his defenses have gone from 100th in total D to 15th last season.

Tony Elliott, Clemson co-offensive coordinator: Jeff Scott got his chance to run a program (at South Florida), so why not Elliott? The two have combined to run Clemson's offense together for the last five years. They've been at Clemson under Dabo Swinney for a total of nine years. Whoever Michigan State hires is going to need offensive promise. The Spartans have cratered offensively the past two seasons. Whatever the future holds, Michigan State will have to be entertaining.  

Tom Allen, Indiana coach: Allen has a similar profile to Dantonio when Coach D got to Michigan State. In 2016, Allen arrived as Kevin Wilson's staff as defensive coordinator at IU. Allen pulled off one of the most dramatic defensive turnarounds in recent memory. The Hoosiers went from 120th in total D to 45th. In 2017, Allen replaced Wilson as coach. The Hoosiers won eight games in 2019 for the first time in 26 years. Allen is 0-3 against Michigan State.

Dave Clawson, Wake Forest coach: Clawson would mark a complete culture change at Michigan State, which might not be a bad thing. Clawson is known for his innovative "Clawfense" spread scheme. His teams typically punch above their weight class. Michigan State administration, fans and players got a good look at Clawson in the Pinstripe Bowl. The Demon Deacons played tough, losing 27-21 at Yankee Stadium. Clawson lost his quarterback, Jamie Newman, who transferred to Georgia. This might be a good time to leave.

Blake Anderson, Arkansas State coach: Anderson's name has made several candidates lists this silly season. He was offered at Missouri but didn't make it through the process after the search became public. Anderson is 47-30 at Arkansas State, having gone to six straight bowls. At this point, Anderson would have to be a fallback option if Fickell or Narduzzi don't take the job.

Matt Campbell, Iowa State coach: As hot as Campbell has been, he would be wise to take a pass on this one. Michigan State is an enhanced version of Iowa State in that both schools have to fight every day against bigger programs in their state. Michigan State isn't exactly set up to win right away either. When Campbell makes his jump up to a better Power Five, he can do better than what Michigan State is right now.