Sehorn's broken bone is the fifth metatarsal of the left foot. The injury occurred during the second of two Rams' practice sessions Sunday afternoon at Western Illinois University, site of Rams' training camp. Sehorn landed awkwardly on his left foot during a passing drill, causing the injury.
"The good thing to this, if there is good news, is we should have him back by the fifth game of the season," Martz said. "That is still a lot of playing time. There is a lot of the season left. We will get him back, but we are going to miss him in the early part of the season."
Sehorn agreed to terms with the Rams on May 19 after spending his first nine NFL seasons with the New York Giants.
"We will move on, but I feel bad for Jason. He was doing so well," Martz said. "He fit in so well and learned our system. It looked like he was making a lot of plays out there on the field. It is just one of those freak things that happened. The thing we have to focus on at this point is that we are going to get him back, and there is an awful lot of the season left to play."
Sehorn will have surgery on Monday in St. Louis.