What is exactly you are trying to achieve? I can think of a couple of different cases
1) If you just want to play the animation as the timeline modifies the X and Y properties you can just play the animation independently of what the timeline is doing.
2) If you want to change the animation frames in relation to the progress of the timeline you could cook something up using the Progress expression of the the Timeline plugin and the AnimationFrameCount expression of the Sprite plugin.
Something like this:
floor(Timeline.Progress("name_or_tags_of_your_timeline") * Sprite.AnimationFrameCount)
That should give you the frame index as a timeline progresses.
3) If you want to set a specific frame as keyframes are reached, you might want to look into keyframe tagging. Those conditions are only triggered when the playhead of a timeline reaches a keyframe.