Agent Mike McCartney confirmed via Twitter on Sunday that Mendenhall had decided to end his playing career after six NFL seasons, all but one of them with the Pittsburgh Steelers.
Mendenhall, the Steelers' first-round draft pick and 23rd overall selection out of Illinois in 2008, gained 4,326 career yards, averaging 3.9 yards per carry.
After signing a free-agent contract with Arizona, he was hampered by a toe injury much of last season and was most effective down the stretch. Mendenhall finished with a team-high 687 yards in 217 carries.
Mendenhall had consecutive 1,000-yard rushing seasons for the Steelers in 2009 and 2010. A knee injury limited him to six games with Pittsburgh in 2012.
Mendenall issued comments about his retirement in a blog-style article through The Huffington post. Click here to read the entry titled, 'Why I retired at 26.'