Kim, the free agent draft in the spring is when you look at the 2013 set and see who can improve your team. There's not much left after our 15 rd draft. For a supplemental draft like we're doing now you want to choose players who are off to a good start for the current 2014 MLB season and hope they continue with their early success. You are basically choosing players who you can use for next years team. Look at who has been picked so far as examples.
As far as seeing who is available you are doing it correctly. I use
Yahoo stats. I Sort hitters by OPS, pitchers by ERA, look who is doing well and then see if they are owned or not from the google doc.