After going from the third overall draft pick to dropped by two teams in three years, running back Trent Richardson knows he is running out of chances to make it in the NFL.

Richardson signed a two-year deal with the Oakland Raiders on Tuesday with hopes that a new team can resurrect what once was a promising career.

"That's a taste that you never want to get in your mouth again," Richardson said of being let go by a team. "Hopefully, this is my last stop, and I'm going to do whatever I can to make this my last stop. Until I'm ready to walk away from the game, I don't want to leave here."

Richardson entered the NFL as one of the most heralded running backs in years after a successful college career at Alabama. Richardson is one of three backs since 1996 to go in the top three picks in the draft, joining No. 2 overall picks Reggie Bush in 2006 and Ronnie Brown in 2005.

But after a somewhat promising rookie year in Cleveland, Richardson has been sent away by teams in his next two seasons.

Cleveland traded Richardson to Indianapolis after just two games in the 2013 season for a first-round pick. Thought to be the final piece needed to solidify an offense led by star quarterback Andrew Luck, Richardson never fit in with the Colts.

Hardy visits Cowboys

The Dallas Cowboys met with free agent defensive end Greg Hardy on Tuesday as they explore ways to improve a shaky pass rush from last season.

Hardy's agent, Drew Rosenhaus, said the former Pro Bowl player for Carolina was visiting Cowboys headquarters.

The 26-year-old Hardy could be suspended to start the season because of a conviction on two counts of domestic violence in North Carolina. The conviction was dismissed in February when his accuser couldn't be found.

Hardy remains on the commissioner's exempt list as he seeks reinstatement by the NFL. He played in the opener last year before he was suspended. Hardy tied a Carolina franchise record with 15 sacks in 2013.

Chargers get receiver

The San Diego Chargers have agreed to terms of a three-year contract with free agent wide receiver Stevie Johnson, who's looking to bounce back after two down years.

Johnson became the first player in Buffalo Bills history to have three straight 1,000-yard seasons, from 2010 to 2012. His best season was 2010, when he had 82 catches for 1,073 yards and 10 TDs.

His production fell off the last two seasons. In 2013, his last with Buffalo, he had 52 catches in 12 games, for 597 yards and three scores.

Last year with San Francisco, he caught 35 passes for 435 yards and three touchdowns.