3 was Warford, 2 was Slay last year.
This means nothing. The transition from college to pro is much easier at guard and much more difficult at CB, which is why Warford was able to contribute so much in year 1 and Slay wasn't.
Plus, we won't be taking another 3rd round guard this year. If we're able to swap 1st round picks and only give up an additional 3rd rounder in order to get Watkins or Clowney, Mayhew better get that done.
If it costs a 2nd instead of a 3rd, then I'd be hesitant for Mayhew to trade up. But losing a 3rd to trade up is totally worth it.