Cleveland's rookie quarterback tossed a trio of picks and lost a fumble that led to Baltimore's first touchdown in a 24-10 win over the Browns.
If that's not enough, Kizer was also hit by a migraine headache that forced him to leave the game for parts of the second and third quarter.
It's the kind of ill-fated outing that can rattle a young signal-caller, but coach Hue Jackson isn't worried about Kizer's mentality.
"He's not that kind of kid," said Jackson, per The Plain Dealer. "He's not going to get rattled by this. He'll go back to work with more resolve. He'll grow from this."
"Everything I said we couldn't do, we did," Jackson said. "You can't turn the ball over to this team; that's how they won their first game. We can't give them that type of field position or take points off the board when you have a chance to make plays. We didn't play well. Obviously, at the quarterback position, you can't give the ball to the other team."
Kizer was also sacked twice and faced steady pressure, but Pro Football Focus notes the rookie has simply struggled out of the gate:
It's no surprise to see a first-year quarterback encounter troubles with decision-making, ball placement and pocket presence. Kizer has also shown moments of confidence and pure arm strength -- looking the part on his better snaps -- but the lack of weapons around him don't help.