Rondo may have called JO, but I think Pierce was the primary recruiter. Pierce and JO share the same birthday and the past few years they have celebrated together before camp started.
It will be very interesting in 2 years to see how Boston is viewed as a place to play. Shaq KG Ray JO will all be up. And we'll be left with Rondo, and older Pierce, and lots of money to spend. But Boston has carried that reputation for not being a popular FA landing spot for many years.