The introduction to the Celtics chapter of Pro Basketball Prospectus 2010-11 basically concludes with a negative note. The book's co-writer Bradford Doolittle writes that "The slippage will be readily apparent on the defensive end in particular. The offseason could have gone very differently for Boston. In a few months, Celtics fans wish it had."

Where is that slippage coming from? We get a better idea from the player comments.

Ray Allen

"His athletic markers also continued to dwindle. Boston can hope the three-point accuracy will bounce back, but everything else should be expected to keep heading in the wrong direction."

Glen Davis

The book projects him for a -7. WARP. If you're familiar with WARP from baseball, a negative number is not great. They hate Baby's play and basically intimated he should be on another team.

Kevin Garnett

"...his on-ball metrics are still excellent." They give Perkins most of the credit for the team's defense in the paint. "His usage rate has also fallen, and 82 percent of his field goals were assisted last year, a 14 percent increase over his first year in Boston. Garnett just can't be counted upon to create as much offense himself."

Jermaine O'Neal

"Last season, he shot the ball well from every distance inside the three-point line, including a .697 mark in shorts at the rim." They don't hate O'Neal, but their WARP system considers him purely a replacement level player, not a former max-superstar who, even at a compromised version of his previous levels, could offer value at the mid-level exception.

Shaq

They are positive about the Shaq signing. "O'Neal is a still a good finisher at the rim, though his percentage dropped seven percent last year and he got more shots blocked."

Paul Pierce

Lauds Paul's .613 TS%. They absolutely love Pierce's consistency and consider him an underrated small forward. "Pierce is aging so well, his contract may turn out to be a solid value."

Rajon Rondo

After a career-best 13.6 WARP season last year, they forecast Rondo returning to his 2008-2009 levels.

The whole book is well worth purchasing. Kevin Pelton and Doolittle did a great job with it this year. I especially love giving ages as 24.8, etc. Nice touch.