  Suppose we are given a Drinfeld Module $\phi$ over $\mathbb{F}_q(t)$ of rank
$r$ and a prime ideal $\mathfrak{l}$ of $\mathbb{F}_q[T]$. In this paper, we
prove that the reducibility of mod $\mathfrak{l}$ Galois representation
$${\rm{Gal}}(\mathbb{F}_q(T)^{\rm{sep}}/\mathbb{F}_q(T))\rightarrow
{\rm{Aut}}(\phi[\mathfrak{l}])\cong {\rm{GL}}_r(\mathbb{F}_\mathfrak{l})$$
gives a bound on the degree of $\mathfrak{l}$ which depends only on the rank
$r$ of Drinfeld module $\phi$ and the minimal degree of place $\mathcal{P}$
where $\phi$ has good reduction at $\mathcal{P}$. Then, we apply this
reducibility bound to study the Drinfeld module analogue of Serre's uniformity
problem.
