How do producers choose between bassists?

[midbass]

I've become a bass enthusiast as of late and really dig into the liner notes to see who played what and all.

What I've noticed is that there can be between 2-5 A-list session bassists on some big name albums.

Anita Baker's "Rapture" had 4 bassists, Donald Fagen's "Nightfly" had 5 bassists, which is a lot considering these albums only had about 7-9 songs, lol.

I'm trying to figure out if the chosen bassist was a better fit for certain songs or maybe he/she was available for certain dates and others weren't??

[superbassman2000]

availability would be one thing, style/groove would also be factored in, and who knows--I know bassists that got the job because the band leader thought they were cool to hang with.

[SteveC]

Aren't a lot of producers bass players?

[chuck3]

Both great albums. No good explanation on "Nightfly" except it seems to be kind of an ultimate session-man album, and it seems like the personnel was assembled song-by-song. Like you said, there were only like 8 songs.

[willgroove2]

If different songs have different producers they may each have their own guy who plays their tracks. I know with Steely Dan Donald Fagin's method was to have multiple rhythm sections all cut the same tunes and they would pick the one that felt right to them so maybe he did the same thing with nightfly.