This isn't an area that I'm expert on, and it's quite possible there's a much more elementary and/or more general answer.

But if the Bass Conjecture on Hattori-Stallings ranks for group rings is true for $G$ then I think the answer is yes. I don't think the conjecture has been proved for finitely presented groups in general, but there are large classes of groups for which it is known to be true.

If $A$ is a ring, and $P$ a finitely generated projective $A$-module, then $P$ is the image of an idempotent endomorphism of a finitely generated free module, given by a square matrix $M$ over $A$, and the Hattori-Stallings rank of $P$ is the image in $A/[A,A]$ of the trace of $M$, which depends only on $P$ and not the choice of $M$.

If $A=\mathbb{Z}[G]$ for a group $G$, then $A/[A,A]$ is a free abelian group on the images of a set of conjugacy class representatives $[g]$, and Bass conjectured that the Hattori-Stallings rank of any finitely generated projective is a multiple of $[1]$. Previously (I think), Kaplansky proved that the coefficient of $[1]$ in the rank is strictly positive if $P\not\cong0$, which, if we also assume the Bass conjecture for $G$, proves that the image of $M$ under the augmentation map must have non-zero trace, so that the image of $M$ under the augmentation map is non-zero, which is equivalent to $P$ having a non-zero map to the trivial module $\mathbb{Z}$.