  Context. Subdwarf B pulsators exhibit pressure (p) and/or gravity (g) modes.
Their frequency spectra range from very simple, with few frequencies, to very
rich, with more than fifty peaks in some cases. Balloon09 is a hybrid pulsating
subdwarf B, showing a large number of p- and g-modes including a triplet and a
quintuplet-like structures which are interpreted as p-mode frequency splittings
due to stellar rotation. Photometric observations undertaken in two subsequent
years revealed a change in these rotational splittings of 0.24 - 0.58
{\mu}Hz/yr. Aims. We analyse the possibility of angular momentum interchange
between stellar rotation and internal gravity waves as a mechanism for the
observed rotational splitting variations. Methods. The expected change in the
rotational splitting of eigenmodes resulting from this mechanism are computed
in the nonadiabatic linear approximation for a stellar structure model that is
representative of the target star. The fact that g-modes are also observed in
Balloon09 makes it a particularly suitable candidate for our study, because the
change in the rotational splittings are proportional to the amplitude squared
of the g-modes which, in this case, can be estimated from the observations.
Results. We find that this mechanism is able to predict changes in the
splittings that can be of the same order of magnitude as the observed
variations.
