Limit function to excerpts in content, not in sidebars

I have this code to allow for some tags in the excerpts, but this also effects the latest posts in the sidebar (genesis featured post widget). Is there a way to limit such code to content only?

add_filter( 'get_the_content_limit_allowedtags', 'get_the_content_limit_custom_allowedtags' );
function get_the_content_limit_custom_allowedtags() {
	return '<strong><h1><h2><h3><a>';
}