Nope, he didn't impede the player. As the player saw the runner going around him, he spun and brought his left shoulder from left to right and rubbed the left shoulder by the blocker. The blocker's left hand was obviously on his left side. His left hand went up on the shoulder pad for a brief split second. The defender is doing a minor acting job as he tried to disengage. He isn't being impeded. The "play" in the photo occurs for a very short split second. The blocker's hand basically slides over the shoulder. This type of contact occurs zillions of times on every play for a split second or more, and it doesn't constitute a penalty.
After looking the photo, you need to go through the life video of the play over and over. Then, you will see that this occurred over about 1/100th of a second and was mostly a brush on over the defender's shoulder. The jersey isn't be grabbed. I think it's perfectly fine for a blockers hands to be on shoulders and shoulder pads briefly.
My view is that the ref probably thought there had been a hold due to the look of the defender, but didn't see any actual hold, that is, illegal hold. You can look at the video 100 times in a row in real time, stopping it and running it back, and not see any holding occurring by the blocker and certainly nothing illegal.