Have to admit I haven't noticed much about Alexander one way or the other. Not a PFF subscriber but searching about him on their site did see they had him graded highly vs. SF and ARZ.

And also this last week:
The Rams are one of two teams where both starting safeties have allowed a catch rate of 50 percent or lower.

This offseason, Los Angeles lost Rodney McLeod to the Eagles, so Maurice Alexander joined T.J. McDonald at safety. The position then projected to be a weak spot in the defense, but so far both safeties have played well in coverage. They have allowed fewer than 100 yards between them when they are the primary men in coverage, and have yet to allow a touchdown