49ers place CB Harris on IR; sign coach’s son

Rookie cornerback Tim Harris, who had an extensive medical history in college, has been placed on injured reserve due to a groin injury he sustained in the second preseason game at Denver. The sixth-round pick had back-to-back medical redshirt seasons (2016-17) at Virginia because of a torn labrum and broken wrist, respectively. Harris figured to have at least an outside chance to make the 53-man roster before his injury, partly due to attrition at his position. The 49ers waived/injured cornerback Greg Mabin (calf) during training camp and it's unclear if cornerbacks K'Waun Williams (knee) and Jason Verrett (ankle) will be ready for the season opener at Tampa Bay on Sept. 8. The 49ers' top available cornerbacks are Richard Sherman, Ahkello Witherspoon, Emmanuel Moseley and D.J. Reed. The situation isn't as dire because free safety Jimmie Ward is likely to replace Williams at slot cornerback in the 49ers' nickel defense if Williams isn't ready for Week 1. Ward played both free safety and in the slot in a preseason win at Kansas City on Saturday, which was his first game since he sustained a broken collarbone in May. The 49ers filled Harris' roster spot by signing cornerback Jordan...