While checking the cable reading after N/D BOP it was found to be negative. Decided to POOH the tubing hanger. While POOH, found that the cable was partially disconnected from the PFT lower connector. The cable reading was checked again after removing the PFT and it was found positive. So decided to lay down one joint and cut the cable to reconnect PFT connecter and land HGR. POOH and lay down HGR+1 joint . Started POOH the second joint and while removing the second band from the cable, it slipped very quickly into the well and during the process the cable wagged and it hit the derrickman on his left arm causing fracture.