Everyone has been wondering why the Browns seem to be collecting running backs. Maybe the reason why is because Trent Richardson is hurt again. Richardson did not participate in the Browns’ OTA practice open to the media on Thursday because of a “pulled lower leg muscle in his shin,” according to a team source. Richardson did view the practice on the field. Afterwards, coach Rob Chudzinski said that Richardson would remain out of next week’s four OTA practices and could also miss the mandatory full-team minicamp June 4-6. “It’s just something precautionary,” Chudzinski said. “We’re holding him out. We have minicamp in a week and a half. He may miss that. I’m not sure. We’ll just take it day by day.” Chudzinski said the injury occurred earlier in the week. The Browns had three practices this week. Only Thursday’s session was open to media. The Browns added two running backs this week. They claimed Miguel Maysonet off waivers from Philadelphia and re-signed Brandon Jackson, who was not initially retained as a free agent. In April, the Browns traded with Philadelphia for Dion Lewis, another running back. “I always felt like you can’t have enough good running backs,” Chudzinski said. Richardson’s rookie season was marked by one health setback after another. After having surgery on his left knee following his final game at Alabama, Richardson needed an arthroscopic procedure in August that caused him to miss all four preseason games. He made it back in time to start the season opener. Once he appeared to be playing himself back into shape, Richardson suffered a rib injury in the sixth game against Cincinnati. Richardson missed the second halves of two games and then averaged 25 carries over the next five games. He missed the 16th game with an ankle injury. After the season, Richardson played the second half of the season with two broken ribs.