What must R1 do when there is excessive blood on his uniform jersey?

When a player has excessive blood on their uniform, it is important for health and safety reasons to address this situation promptly. Changing the jersey immediately with a teammate is the appropriate action in this scenario. This ensures that the player can continue to participate in the game without compromising safety standards or risking the health of themselves or other players. Blood on a uniform is considered a violation of the playing equipment rules, as it poses a potential risk for spreading infections.

The other options are not suitable responses to this situation. Using a special cleaning solution on the field does not provide a practical solution to eliminate the problem quickly, as the uniform needs to be completely clean and free of blood to comply with regulations. Wearing any available shirt to continue playing could lead to confusion about the player's team affiliation or might not meet uniform standards. Lastly, asking for permission to use a different colored shirt does not address the immediate need to change the jersey and could delay the player's return to the game unnecessarily. Thus, changing the jersey immediately is the most effective action to ensure player safety and compliance with the rules.