Bill Bradley -- If The Knicks Need Someone ... I'm Available

Bill Bradley clearly agrees with Aaliyah about that whole "Age Ain't Nothing But A Number" thing ... 'cause at 71 he tells TMZ Sports he's willing to suit up for the struggling Knicks RIGHT NOW.

The former Knick -- and U.S. Senator -- was out in D.C when we asked him what exactly the Knicks need to get them out of the kingdom of suckdom that they have resided in all year.

"I'll go back for the average salary as a designated free throw shooter," Bradley said.

He was obviously joking around ... but he definitely turns serious when asked how many years he thinks it'll take his friend Phil Jackson to turn the team around.