Is it possible in Bash 4.0 to substring and uppercase a variable in one

Given a variable var=toucan I can do the following:

echo ${var^^}
TOUCAN
echo ${var:3}
can

Is it possible to do something similar to echo ${var:3^^} to get CAN?

echo ${var:3^^}
bash: var: 3^^: syntax error: operand expected (error token is "^")