After I was first introduced to foam rolling I would have said yes. It seemed so much more effective than stretching for me personally. Then I'd run into trainers that want nothing to do with foam rolling and swore by stretching. So where is the disconnect, what is the difference?
The area of focus is the difference. Foam rolling most effectively targets a specific area while stretching warms up the entire muscle (or groups of muscles). Static stretching evenly warms up a full muscle from insertion to origin while dynamic stretching takes it one step further and warms up the group of muscles recruited in that movement.If you are trying to foam roll to warm up an entire muscle group it is probably not the most effective way to go about it. If you feel tightness in a specific location, like a "knot", foam rolling will likely be more effective as you can pin point the areas of discomfort.
When muscles and body tissues are hydrated, healthy and functioning properly dynamic stretching is probably your best bet. Ah ha! I think that is why many trainers don't see the bang for the buck in their case with foam rolling compared to a quick dynamic stretch.