Minnesota DNR website, I don't see it looking very like any of the frogs - but not strongly like any of the toads, either. The pale line right down the spine is suggestive of the American toad, but the outline of our little guy seems much smoother than that. I would in general more easily expect to find a toad than a frog in a garden, but the backyard neighbors have a swimming pool and we quite often hear what we believe are frog sounds from that direction in the summers. We didn't see ours hop away, didn't get a look at the feet, and didn't hear it make any sounds.
So, any experts out there?