Berry released a statement on Monday regarding his health condition that has shocked his team-mates, Chiefs fans and the NFL.
His agent, Chad Speck, said he found out on Saturday that the 25-year-old "potentially has lymphoma".
In a statement, Berry said: "I am truly thankful for all of the support from family, friends, coaches, teammates and the entire Chiefs kingdom.
"At first I was in shock with the diagnosis on Saturday and did not even want to miss a game, but I understand that right now I have to concentrate on a new opponent.
"I have great confidence in the doctors and the plan they are going to put in place for me to win this fight. I believe that I am in God's hands and I have great peace in that.
"I know my coaches and team-mates will hold things down here the rest of the season and until I am back running out of the tunnel at Arrowhead.
"I am so thankful and appreciative of being a part of this franchise and playing in front of the best fans in the NFL. I will be back."
Berry has been placed on the team's non-football illness list, ending his 2014 season.