Ndamukong Suh was fined $100,000, but not suspended, this afternoon for a low hit in the Detroit Lions' victory over the Minnesota Vikings on Sunday, the National Football League said.

While the fine is a sting to his pocket book — Suh has a five-year, $65.3 million contract and can appeal the penalty — he can write off the $100,000 on his taxes.

Under federal tax law, on-field NFL fines are considered a business expense, and thus tax-deductible. Fines for off-field issues, such as arrests, are not tax-deductible.

Under federal tax rules, a $100,000 fine would result in a tax benefit of approximately $8,000, so the actual cost to him would be $92,000, said Robert Raiola, a New Jersey-based CPA and sports and entertainment group manager with Fazio, Mannuzza, Roche, Tankel, LaPilusa LLC. He specializes in tax planning for individuals and their families in the sports and entertainment industries.

The fine is believed to be the third-largest in league history, after the NFL levying $500,000 on New England Patriots coach Bill Belichick in 2007 for illicitly filming an opponent's practices, and $250,000 on former Baltimore Ravens linebacker Ray Lewis for making false statements to police after a post-Super Bowl double murder in 2000.

Suh, who is saddled with a reputation as a dirty player for a history of on-field incidents, was flagged early in the second quarter on Sunday for hitting the knees of Vikings' center John Sullivan after Detroit linebacker DeAndre Levy intercepted a tipped Christian Ponder pass and returned it for a touchdown to give the Lions the lead.

The penalty erased the score, although the Lions went on to later win 34-24.

Sullivan was trailing about 10 yards behind Levy with no hope of catching him when Suh took out his legs.

"I wasn't by any means going for his knees," Suh told reporters after Detroit's victory. "He knows that. We had a great conversation running out at halftime, and he understood. My aim was his waist to cut him off.

On Monday, Detroit head coach Jim Schwartz told reporters that Suh was trying to avoid hitting Sullivan in the head.

"What he explained to me was he didn't want to hit him high because if he hits him in the head right there it's a peel-back and that's a penalty also," Schwartz said in comments provided by the Lions. "He was trying to hit him at the waist and ended up in a bad spot and went low. It's a penalty."

Suh, 26, has been flagged 11 times for personal fouls in his 47 career games.

He's been fined a variety of amounts for mishandling quarterbacks: $20,000 for Cincinnati's Andy Dalton; $15,000 for Chicago's Jay Cutler; $7,500 for Cleveland's Jake Delhomme; and $30,000 for Houston's Matt Schaub.

In 2011, he was suspended for two games without pay for stomping on Green Bay Packers offensive lineman Evan Dietrich-Smith's arm during the nationally televised Thanksgiving Day game. The Schaub incident, which appeared to be a kick at the quarterback's groin area, was during last year's Thanksgiving game.

Fines are part of the NFL's collective bargaining agreement with the National Football League Player Association.

The NFL gives the fines to charities.

"All on-field player fines collected by the league are donated through the NFL Foundation to assist former players in need via the NFL Player Care Foundation and the NFLPA's Player Assistance Trust," said Randall Liu, the NFC director of communications, in an email to Crain's this afternoon.

The fines are split between the charities. The NFL said the fines have netted about $4 million annually for several charities.

Minimum fine amounts increase 5 percent annually under the labor deal, according to an outline of the fine rules provided to Crain's by the NFL.

However, the 2012 fine amounts have remained the same this season because "players have adjusted to the rule," the league said in its outline.

The number of fines have declined 32 percent since 2009 (451 last year from 668 in 2009).

The NFL has the authority to impose higher fines and other discipline, such as suspensions. A player's history is a factor in discipline, the league said.

Fines and other penalties are typically levied on the Tuesday following a Sunday game, and players have three days to notify the league they intend to appeal.

A hearing is conducted on the appeal within 10 days. Under the labor deal, former coach and player Ted Cottrell and former player Matt Birk conduct the hearing and make a decision.

If they uphold the fine, the money is deducted from a player's paycheck. Players are paid weekly during the season.

Suh's latest fine was first reported today on Twitter by Jay Glazer of FOX Sports. The NFL announced it shortly after that.

Suh's fine isn't much of a financial burden for him.

In March, he and the Lions renegotiated his contract and shifted money around to create $7.68 million in salary cap space for the team this season.

His base salary in 2013 is $630,000 with an $11.5 million bonus — money that will be paid over the final three seasons on the contract.

However, reworking his contract means he counts against the 2014 salary cap by a whopping $21.4 million, which is unsustainable. The cap for 53 players on the roster will be around $120 million to $130 million. So, he likely will be renegotiated again before next season, or he will be given an extension to alleviate the salary cap pressures.

He also gets a $125,000 workout bonus.

Detroit took Suh with the No. 2 overall pick out of the University of Nebraska in 2010. He was All Pro as a rookie.