The team did not even get a 'sniff of' the play-offs last year. [=did not even come close to reaching the play-offs]
It's not a big profit, but it's 'not to be sniffed at'. = It's not a big profit, but it's 'nothing to sniff at'.
Several companies, 'sniffing' [='sensing'] profit potential, are investing in the area.
(..) and we sort them over there. I hope you work out, all right? The last guy they sent me... ...didn't wear no drawers, couldn't read the sizes in the drawers... ...and used to sniff the drawers. We got two sizes: Medium and large. All right? All you do is put the mediums with the mediums... (..)1998 American History X