Anybody who saw Jimmy Smith gingerly walked off the indoor practice field Thursday wasn't shocked by the Ravens cornerback's absence during Friday's session at the team's headquarters in Owings Mills.
"Jimmy's back locked up," Harbaugh said Friday. "It's all muscular. It's stuff that has happened to him in college before. It takes a couple of days usually for that to loosen up."
Harbaugh also cleared up the mystery of defensive end Arthur Jones, who was not present for the second straight day.
"Arthur got an MRI," Harbaugh said. "He had a hip flexor issue that he has been fighting through for the last couple of days, so we decided to get it looked at. I have not heard the results of that. [We] don't expect it to be serious, but we wanted to check it out and make sure."
Finally, Vonta Leach's back began giving the fullback problems. So Leach, who at the age of 30 is a member of the 30-and-over club, was given the day off.