Can someone ID this grass?

This grass has appeared in a salt-killed sun-baked patch next to my driveway. I used some Pennington 1 Step complete in a bare spot right near this area, so it got regular watering as that new seed was taking root. This is not that seed. The pennington stuff is mixed with a papery mulch, so I know where it was placed. That grass is a deep green and very thick right now. This grass is different; It has very fine blades, is rather sparse (probably due to bad soil right there), and is a pale or yellowish green. It actually looks pretty fragile, but I like the super fine blades.

If you don't get an answer, try letting a small patch flower/go to seed and post a picture of that. It is much easier to identify grasses from the seed heads.

Might be one of the filler seeds that green up quick, like annual ryegrass.

Thanks. I'll take pictures if it goes to seed.

I always thought annual ryegrass was crab grass.

grab some of it and pull, if it comes up with shallow roots you have rough blue grass growing there. if not then it is a perennial rye.