STUMPERS XIII

If you remove two letters from the word STANDARD, the remaining six letters share an interesting quality. After the two letters are removed, no re-arrangement of the remaining letters is necessary. Can you determine what this interesting quality is?

HINTS:
#1: The two A's need to be removed.
#2: Leave the spaces open after removing the two A's.

Answer:

Removing the two A's from STANDARD leaves
ST ND RD - as in 1st. 2nd, 3rd.