"LenDale White knew for months that he would miss the first four games of the NFL's 2010 season while serving a league-mandated suspension.

The Broncos running back learned Friday that he will miss the rest of the season as well after being diagnosed with a torn Achilles tendon, an injury that will require surgery and lengthy rehabilitation.

White was injured Thursday night at the end of a 9-yard gain during the second quarter of the Broncos' preseason finale against the Vikings at the Metrodome in Minneapolis.

The Broncos initially said White had an ankle injury. White left the stadium on crutches, with his left foot and lower leg heavily wrapped.

This is the latest setback in what has been a difficult year

for White, a Chatfield High School graduate who starred at Southern California.

He was traded by the Tennessee Titans to the Seattle Seahawks during the NFL draft in April. But his stay in Seattle - where he was reunited with his USC coach, Pete Carroll - didn't last long. He was cut in June, just before the NFL announced that he would be suspended for the first four games of the season because he violated the NFL's substance-abuse policy.

The Broncos signed White on Aug. 4 to help bolster a backfield depleted by injuries to Knowshon Moreno and Correll Buckhalter. But White was injured in his first full practice and missed Denver's first two preseason games. He scored a touchdown in the third and fourth preseason games."