This doesn't look like crabgrass, but we can't tell exactly what it is just by these photos alone. Would you be able to send additional pictures showing the grass's growth habit in the lawn (is it spreading or clumping or a few sprigs randomly dispersed)? Have you been irrigating at all? If you can pull a whole plant out carefully and show us near the root crown, that might also help to see some more of its characteristics (looking for tillers, stolons, etc). There are a lot of different features to look at for identifying grasses. Sometimes, we cannot identify them without seeing the flowers or seedheads, but if you can provide additional details, we will see if we can determine what it is.

Christa