While all reports Friday morning indicate that Paul Pierce has indeed re-signed with the Celtics after opting out earlier in the week, it's important to note that nothing is yet completely official (and can't be until July 8).
In fact, the Boston Globe is reporting that "a source close to the negotiations said that the deal is not done." But Pierce wants to remain a Celtic, and Boston is the only club he's negotiated with, so all signs still point to The Truth staying in the Celtics' green. The hold up right now is the fourth year of the contract.
Steve Bulpett of the Boston Herald, who originally broke the news, reports that it was confirmed to be a four-year deal worth $61 million, adding that there is a mutual option after the first three years. However, Fox Sports' Jeff Goodman says that all four years are guaranteed.
A four-year deal is important, because it would earn Pierce a no-trade clause in the contract, likely ensuring he would retire with the Celtics.
The value to the Celtics is having the option to cut most of his salary from the books in the 4th year (or trade him to a team looking to cut payroll). The value to Pierce (other than the extra money) is getting a no-trade clause (that only kicks in if he signs for 4 years). Sounds like a win-win.
At this point, it seems that just the final details need to be worked out in a deal that will have Pierce ending his career with the Celtics.