Running back Rashard Mendenhall announced Sunday he was retiring from the NFL

Rashard Mendenhall will be a free agent Tuesday, but the Cardinals will not be re-signing him. The veteran running back, in fact, won't be signing with anyone.

Instead, Mendenhall – who doesn't even turn 27 until June – announced his retirement from the NFL Sunday, a couple of weeks after hinting at as much on his blog on the Huffington Post. He played just six seasons. Mendenhall confirmed he was leaving the game on the same blog.

"I actually didn't really plan on saying anything about my retirement at all," Mendenhall wrote in his latest piece. "I just kind of wanted to disappear."

Mendenhall, who signed a one-year contract with the Cardinals this time last year, battled through knee and toe problems all

season. He gained a team-leading 687 rushing yards and eight rushing touchdowns as the grinder part of the rushing offense, paired with rookie Andre Ellington.

Mendenhall has always been a thoughtful sort, talking a lot about his poetry and his love of reading and books. Yet he wrote it was his old-school philosophy toward football that ultimately helped him decide he didn't want to play anymore.

He wrote of all the times he had been called a racist slur as a public figure playing football, but "what was more difficult for me to grasp was the way that the business of entertainment had really shifted the game and the sport of football in the NFL. The culture of football now is very different from the one I grew up with."

Mendenhall didn't come into the league until the Steelers drafted him in 2008, but he laments the changes in the game like players dancing after touchdowns and how fantasy football has impacted how players are seen.

"This is a very different model of football than the one I grew up with," Mendenhall wrote.

"So when they ask me why I want to leave the NFL at the age of 26, I tell them that I've greatly enjoyed my time, but I no longer wish to put my body at risk for the sake of entertainment," Mendenhall wrote. "I think about the rest of my life and I want to live it with much quality. And physically, I am grateful that I can walk away feeling as good as I did when I stepped into it."

For the Cardinals, Mendenhall's retirement is not a shock. Ellington and Stepfan Taylor are the early favorites to carry the running game in 2014, and the Cards still have Ryan Williams on the roster. Drafting a back in the later rounds or picking up a cheap veteran is still a possibility.