The play-off Kansas City Chief will be without Alex Smith on Sunday after the quarterback was diagnosed with a lacerated spleen.
Smith took a shot to the abdomen during the Chiefs' 20-12 loss to the Pittsburgh Steelers on December 21 and even trained twice throughout the week.
But Chase Daniel will start in place of Smith against the San Diego Chargers in the regular-season finale after tests at Kansas City University Hospital uncovered the significance of the injury.
Chiefs trainer Rick Burkholder said Smith does not require surgery, while the recovery time is generally six weeks.
"I didn't notice anything. I walked Rick through the game. I'm kind of guessing as far as the hit," Smith said on Friday.
"I think it was that one, but it wasn't until after I showered up, even dressed, adrenaline kind of got out of me and I noticed some discomfort for sure in my stomach area. Pressure, cramping and I thought it was, I don't know, something I ate. I didn't even necessarily relate it to a hit. But definite discomfort down there.
"I went and saw Doc, he examined me. [He] told me some things to kind of keep an eye out for. I literally took some antacid stuff there. I didn't know what to make of it and it just didn't go away.
"I practiced on Tuesday, I worked out on Monday, I ran. It certainly wasn't something that was prohibiting me athletically. I didn't feel like it was muscular. I just kind of had this discomfort.
"Nausea [was] kind of coming and going. I knew a bug was going around. I thought maybe it was that. Like I said, I practiced both days, I felt great athletically running around, throwing.
"Kind of just had this constant deal going on and thankfully Doc kind of urged me to get the test. I was pretty reluctant yesterday, Christmas Day. I was telling him I'm fine. I'll be alright. He really kind of pushed me to go get it checked out and make sure everything was OK.
"Then I obviously got the call and get told I had the laceration on there and it was enlarged and so, I was learning this all of last night."
The Chiefs (8-7) - third in the American Football Conference (AFC) West division - must beat the Chargers at Arrowhead Stadium and see the Baltimore Ravens and Houston Texans both lose to make the play-offs.