  The yrast band in the heavy $N = Z$ nucleus $^{88}$Ru is studied in the
framework of the $\alpha$-cluster model in combination with double-folding
potentials. It is found that the excitation energies of the yrast band in
$^{88}$Ru can be nicely described within the $\alpha$-cluster approach using a
smooth and mildly $L$-dependent adjustment of the potential strength. This
result is similar to well-established $\alpha$-cluster states in nuclei with a
(magic core $\otimes$ $\alpha$) structure. Contrary, the yrast bands in
neighboring $N \ne Z$ nuclei deviate from such a typical $\alpha$-cluster
behavior. Finally, the $\alpha$-cluster model predicts reduced transition
strengths of about 10 Weisskopf units for intraband transitions between
low-lying states in the yrast band of $^{88}$Ru.
