To me, it sounds like the third verse of "My Baby Left Me" starts with the lines:
Baby, one of these mornin's, Lord, it won't be longYou'll look for me, baby, and daddy will not know
although some internet sources I referenced transcribe the lyrics (with odd line breaks) as
Baby, one of the morningsLord, it won't be longYou'll look for meBaby, and daddy, he'll be gone
In any case, the second verse of "Groovin'" starts with nearly identical lines:
One of these mornin's and it won't be longYou'll look for me, and I'll be gone
Because the lines resemble each other so closely, I think this is an intentional similarity, but I'm not certain.