The 49ers face the Broncos on Sunday at Levi's Stadium, and second-year cornerback Ahkello Witherspoon learned of Sanders' injury. He said he was looking forward to the challenge of facing him.
"That hurts," Witherspoon said. "As a competitor, you want to go against the best. You see him as a person, I feel for him. I wish him the best."
The injury, however, did not impact Witherspoon's preparation for Sunday's game. He said as part of his weekly routine, he does not begin studying the opposing receivers until Friday evening. It is a change in preparation he has made this season after working with veteran Richard Sherman.
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"Friday night and Saturday night, that's when I go into the personal stuff, those third downs when you're going to be one-on-one with the X (receiver)," Witherspoon said. "What does the X like to do? And I get really intricate and look at the release and stuff like that.
"Last year, I did more and was trying to break down all kinds of stuff. I was looking at too much information and not retaining enough. With the help of Sherm, and his ability to retain information as well, he told that less is more throughout the week."
On a typical week, Witherspoon said on Wednesdays he concentrates on first and second downs. His focus shifts to third downs on Thursday. On Friday, the entire plan is in place for review. Then, he focuses on the nuances of the players he will be assigned to cover.
The Broncos no longer have their top two receivers from the beginning of the season. The club traded Demaryius Thomas five weeks ago to Houston. Now, Witherspoon will adjust his film study to prepare to match up mostly against rookie Courtland Sutton and DaeSean Hamilton.
Witherspoon has experienced an up-and-down second season. After struggling early in the season, he is playing much better in coverage in recent weeks.
On the season, the opposition has targeted him 62 times with 35 completions for 407 yards and five touchdowns, according to Pro Football Focus. On the other side, Sherman has given up 18 catches on 31 targets for 305 yards and one touchdown.
"I like where I'm progressing," Witherspoon said. "I'm never really happy with where I am. I like the steps I'm taking throughout the course of the season, the good, the bad, the in-between. I'm just trying to keep growing, keep working and keep getting better."