Using this year's draft as example would look something like this. We don't need Clowney, so picking him at 2 with the intention of playing him at DE alongside Long, Quinn, and Hayes would not be a smart move. However, if he fell to us at 13, we'd have to think long and hard about pulling the trigger.
I had SJ going in the first half of the first round, and Chris Perry to the Rams at 26. In the end, the Rams moved up for SJ after he unexpectedly dropped to #24. Perry went at #26, as I had predicted.
Prior to the draft, when I published my mock, there were some who said I was crazy to think the Rams would take ANY RB in the first round.