It sounds like it would just be a clean up procedure, probably something with the meniscus. Which is definitely a minor procedure.
When I was a senior in high school I tore my meniscus while running on a sand bar on the Missouri River. When I went to the doctor he told me when can either remove what was torn off or sew it back together. This was back in 1996. The recovery time was quite dramatic between the two. To just remove the portion that was torn I would be back to running cross county and playing football within a couple weeks. To sew it back together the recover time would have been 4-6 months. Being that it was my senior season and I had scholarships on the line, and knowing that I would have arthritis due to the removal, I still said lets take it out. I started at FS for my high school team 9 days after the surgery and then ran a cross county race the next day.
I have no doubt that if it is a simple clean out procedure that Moreno will be ready for training camp.