According to SI’s Chris Mannix, the Celtics were divided about whether to sign Shaq. Maybe they should call him the Great Divide. (WEEI)

Mannix said it’s a one-year deal for the veteran minimum — approximately $1.4 million — with a second-year player option. “This was not an easy decision for either side,” Mannix said, adding, “Shaq is obviously taking a monster pay cut. … It’s a huge, huge pay cut for this guy to play for this team and to accept a reserve role, coming off the bench.

“And for the Celtics, I can tell you this much, it was not a unanimous decision. This is not something that the entire front office and coaching staff entirely agreed upon. But it is a Danny Ainge type of move. He’s taken risks like this in the past, whether it’s Gary Payton or Stephon Marbury or Nate Robinson this past year. He’s taken chances on guys he thinks can help put them over the top. Danny obviously is convinced that Shaq is what this team needs right now.”

Asked if it was Shaq’s off-court distractions or on-court issues that made the Celtics hesitate, Mannix said: “It’s a little bit of a blend of both, but I think you’d have to start with the on-the-court problems. He is the worst pick-and-roll defender of all-time. He really is. He’s just a horrible, horrible guy when you’re coming off blitzing those screens. And Kendrick Perkins was one of the better pick-and-roll defenders on this Celtics team. This whole defense that Tom Thibodeau put together, and Kevin Garnett glued together, was based on effective pick-and-roll defense.

By the way, Shaq — who Mannix referred to as “the worst pick-and-roll defender of all-time” – might not actually be as bad as we think when it comes to pick-and-roll defense (even though he defends it as a beached whale might). As Tom Haberstroh tweeteth, “Morning NBA tidbit: [According] to Synergy, Shaq 10th most oft-attacked [pick-and-roll] big, scored on 42.2%, just like Duncan, better than Millsap, Bosh, Odom.” So maybe that whole Shaq is horrible defending the pick-and-roll thing is a little overrated. Although, have you ever seen him try to defend it? It’s not exactly awe-inspiring.