Sips: resize image's smallest side, not largest side

The command sips -z 2000 image.jpg will resize the biggest side of an image to 2000 if it is greater than 2000, while preserving the original aspect ratio. Is there a similar command that will resize the smallest side of an image to 2000 if it is greater than 2000, while preserving the original aspect ratio? The rationale behind this request is that if I try to downsize the greatest side of an image to 2000, it will greatly affect the resolution of panoramas and other long/wide images.