The 24-year-old told reporters: "It's definitely tough for me. Brandon is definitely a leader in the room and I was learning a lot from him being a professional on and off the field.
"It's a big loss and at the same time I'm next up in line and I've got to step up for the offense. Coaches like guys that can go out there and catch the ball with their hands and that's what I try to do.
"I try to catch every ball thrown my way and just make a play when I can. Since OTAs I've been backing up each position and I've been playing this position since last year and it's just go out there and try to make plays and catch the ball when it's thrown my way."
Matthews has 93 receiving yards so far this season.