49ers quarterback Nick Mullens is getting his first NFL playing time this season and it’s been a learning experience on many fronts.One of the ways to learn is by making mistakes and Mullens did that while running the victory formation in a win over the Broncos last month. He learned another lesson on the final play of Sunday’s 14-9 loss to the Bears.Mullens was rolling to the right on fourth-and-five with ample running room in front of him to pick up a first down with just over a minute left to play Christian Miller Jersey , but he chose to try a low-percentage throw to wide receiver Marquise Goodwin in the end zone. The ball was incomplete and the 49ers had their sixth one-score loss of the season.“I should have ran,” Mullens said Jordan Scarlett Jersey , via the . “I didn’t run. In the heat of battle things happen fast. You make split-second decisions. I saw Quise down the field and tried to give him a chance instead of making the simple play.”The 49ers may have lost the game after Mullens ran for a first down and it certainly wasn’t the only chance they missed to make a play over the course of the afternoon, but it was a lamentable mistake that Mullens wanted back “the second I threw it.” When an NFL player takes a hit to the head and shows symptoms of a concussion — such as struggling to balance as he lines back up for the next play — a medical spotter is supposed to signal to the referee to take him out of the game. That didn’t happen with Giants wide receiver Sterling Shepard on Sunday David Montgomery Jersey , and the league and union want to know why.A review of the circumstances under which Shepard remained in Sunday’s loss to the Cowboys is being conducted by the NFL and NFL Players Association, Adam Schefter of ESPN reports.Shepard took a hard hit on a collision with Cowboys cornerback Anthony Brown and struggled to get up. The Giants’ medical staff appeared to be on the way to check on Shepard when he waved them off and remained in the game.It was revealed this week that Shepard did suffer a concussion and has been ruled out for Week Two.