BEREA, Ohio (AP) - Browns running back Trent Richardson is not practicing again because of a shin injury that could keep him sidelined for an extended period.

Richardson worked on his conditioning Thursday while his teammates went through the final session of organized team activities under first-year coach Rob Chudzinski. Richardson also missed last week's OTAs and Chudzinski said the second-year back could miss next month's mini-camp.

The Browns said Richardson has a strained muscle in his shin. The injury doesn't appear to be serious.

As a rookie, Richardson missed the exhibition season while recovering from knee surgery and played most of the year despite having two broken ribs. The first-round draft pick still managed to rush for 950 yards with 11 touchdowns.

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