The Bears' injury-depleted receiving corps suffered another blow during Tuesday's Family Fest practice at Soldier Field.
Veteran wideout David Moore exited the workout after getting tangled up with a defensive back on a long pass pattern down the left sideline.
"It's just next-man-up," St. Brown said. "It's football; injuries happen. You hate to see your fellow teammates go down, but in the middle of practice, the next person has to step up and fill the shoes up of wherever we are missing guys at. You hate to see it and it happens every year, but yeah, people have to step up."
Tuesday marked the Bears' 11th practice of training camp and their fourth in pads. They'll work out Wednesday and Thursday in preparation for Saturday's preseason opener against the Chiefs at Soldier Field.
St. Brown feels the Bears offense has steadily improved.
"I think we are making big strides throughout camp," he said. "OTAs helped us a lot for us to get the offense in. Now, we are in camp with the pads on and I think these last few practices, we have made big strides as an offense, 11 players on the field working as one. I think we will be ready for the first game."
Coach Matt Eberflus acknowledged the challenges in being thin at a position such as receiver.
"It does make it difficult," he said. "You lose men on a 90-man roster and it makes it difficult for the other guys. We're at that situation where we've got to just keep on working through it. Next-man-up and the whole roster is going to get more reps at that position, so that's where we are."