Here's what we know (and thought we knew) about Jonathan Papelbon:

He's the best closer in Red Sox history, and that isn't up for debate (I suppose I could allow Dick Radatz a seat at the table, but I think given A) Papelbon has four seasons with an ERA+ better than Radatz’s best season, and B) all the postseason stuff, it's not even really a serious conversation.)

He's never again going to be the pitcher we saw in 2006 and 2007 (in '06 he was the second pitcher in history to save more than 30 games with an ERA under 1.00, in '07 he had a WHIP of 0.77, averaged 13 strikeouts per nine innings in the regular season and 10 2/3 scoreless innings in the postseason, and had three saves in the World Series.) That was ridiculously, historically brilliant stuff that was understandably not appreciated at the time. We just assumed this was going to be what Papelbon (26 years old in 2007) was. Turns out we were wrong. He was a very good closer in 2008 -- I might even give you great -- and 2009 and just another guy in 2010.

And we all knew that this would be his last season in Boston, right? Theo isn't going to pay $35 million for 50 innings a season, Bard looming, Papelbon in decline, all that stuff. 

Except this happened: Papelbon has returned from his hiatus to rejoin the list of elite closers in baseball in 2011. His WHIP (0.93) is his best since 2008, his 11.5 strikeouts per nine innings is his best since 2007 and his 8.13 K/BB ratio is the second-best of his career (and how about these post-All Star Game numbers -- 16 innings, five hits, one run, 17 strikeouts and zero walks). He's passing the stat test, the eye test and even the "Do you feel like the the game is over when he comes in?" test.

(If you take even a quick glance at the numbers, Papelbon's slide toward the middle in 2009 and 2010 was due only to walks. That's it. The strikeouts were about the same and hits per nine were about even with 2008. But control was the root of the Papelbon problem. In his first four seasons he walked a total of 53 batters in 230 innings and in 2009 and 2010 he walked 52 batters in 135 innings. In 2011? Eight walks in 52.2 innings.)

So, having watched Papelbon this season, here's what else we know:

The Red Sox have to sign him. Or at least make every realistic effort possible.

I don't expect the Sox to give Papelbon a five-year deal, or $20 million more than any other offer. Nor should they, of course. But a competitive offer should be made -- think two years, $26 million with an option for a third. If he gets a better offer from the Phillies or Cardinals or another team and decides to jump, that's how it goes. 

Look, does it make perfect sense to pay a guy pitching 60 innings a year $13 million a season (comes out to about $216,000 an inning)? Nope. But sometimes you have to overpay for something resembling a sure thing. And this isn't the Royals we are talking about -- this is a team with a $160 million payroll. Things are just different -- the Sox can afford to spend $15 million on Mike Cameron and $12 million on Bobby Jenks.

And let's also be fair about this: Even the Papelbon of 2010 isn't close to a disaster at $13 million. Let's assume he falls somewhere in between what we've seen last year and this year. Couldn't the Sox do a lot worse with that $13 million than make the ninth inning something they don't have to worry about for the next two or three years?

Also this: If Papelbon leaves, do you have any faith in Theo to use that $30 million -- assuming the Sox do in fact spend it -- wisely? I don't -- quick, someone get me that list of terrific multiyear free agent deals Epstein has made in his tenure as GM. There isn't one in the group, but plenty of stinkers. I'll gladly put Theo up with anyone when it comes to building a farm system, and his trades have been more hit than miss, but his free agent track record is pitiful. 

I don't know about you, but I'd overpay a little and take my chances with Daniel Bard and Papelbon over just about any eighth-ninth-inning duo for the next two or three years. Take a look around the league -- it's seems near impossible to build a bullpen and is even harder to find a back of the bullpen that can dominate a month or two and potentially carry a team through a postseason run. Again, why mess with Bard/Papelbon in the eighth and ninth inning? (In the postseason it might be the two of them splitting the final nine outs. Take Papelbon out of the mix -- how would you feel about Bobby Jenks or Matt Albers or Free Agent X trying to get four or five outs in the eighth or ninth inning of a one-run Game 7 of the ALCS?) A combination of Bard and Papelbon is something teams look for when trying to build a World Series winner, not let go in the hope that Bobby Jenks might "figure it out."

Ah, but there is The Bard Dilemma. The Closer in Waiting probably wouldn't be thrilled if Papelbon returned, and that's understandable. And while it's important to keep Bard on board with the program, does anyone think he'll be less productive if he's forced to be the eighth-inning guy for the next couple of years? Sure, maybe he'll tell the media next February that he wants to be a starter -- and it'll be a nice one-day story for the media to chew on -- and that'll be it. And this isn't a knock on Bard, who has done nothing to suggest that he would be anything less than a superb closer. It's more a statement, in fact, of how good Bard is in his role. Replacing Papelbon with Bard probably wouldn't be much of a downgrade at all. But who do you replace Bard -- and his 2.10 ERA and 0.81 WHIP -- with? Jenks? Wheeler? Albers? Miller? Dubront? Find me a sure thing in that group.

The MVP race. The battle for the AL East. The No. 3 starter in the postseason rotation. The health of Clay Buchholz. The Curious Case of Carl Crawford. All compelling storylines heading into the playoffs, and it's almost easy to forget this:

There's a very good chance that the best relief pitcher in Red Sox history will be out of town in two months.

Jonathan Papelbon should be back. But will he be wearing a Sox uniform in 2012?

No one knows.