SANTA CLARA, Calif. — It was a slow build. Christian McCaffrey took a shot from a linebacker early in Friday’s practice, then later was hit low during a run up the middle.When the running back made a contested catch on the sideline, he reacted with fist pumps befitting a third-down conversion in November.Finally, as the San Francisco 49ers’ first padded training camp practice came to a close, McCaffrey flung the ball at linebacker Dre Greenlaw after a catch and tackle, and some shoving ensued. Right after that, linebacker Fred Warner and tight end Jake Tonges got into it, and another scrum formed.No punches were thrown, and the 49ers seemed to walk the line of training-camp intensity and pseudo-violence perfectly.“When you get guys competitive, it doesn’t matter if it’s a veteran or leader — in competitive situations, fuses get lit. Guys are trying to set the tempo and tone,” said assistant head coach Chris Foerster, who is standing in for injured head coach Kyle Shanahan.“I don’t think it’s anything more than a Day 1 issue.”Maybe there are some residual sore feelings from the injury running back Jordan James suffered on the second day of training camp. Foerster said the team believes James’ ribs were cracked from Warner punching at the football and James spinning to avoid a fumble.When asked what it’s been like playing in front of Warner and Greenlaw, defensive tackle Osa Odighizuwa chuckled.“Fred has just a menacing aura,” he said.Later, when asked his impressions of rookie running back Kaelon Black — a camp standout — Odighizuwa said he had no idea who that was.Early standouts from 49ers training campVic Tafur and Matt BarrowsOdds and ends• The 49ers are “continuing to evaluate” Ricky Pearsall’s right knee, Foerster said, after the receiver aggravated the injury he originally suffered to his PCL in September. Surgery remains a possibility.Dr. Eric Giza, chief of orthopedic foot and ankle surgery at UC Davis and head physician for the Sacramento Republic FC soccer team, said there’s better blood flow to the PCL than the ACL, and it often can heal on its own, which is the approach the 49ers initially took with Pearsall.