Rasheed's PER of 13.29 ranks him 184th in the league in that category
So what you're saying is that our backup big man who is making the MLE has performed at slightly below the league average player? In other words, his 13.29 means that he should be designated as a backup. Surprise! He is a backup and not a starter for this team.
Rasheed Wallace (22.5 mpg, 13.29 PER)
Salary: $5,854,000
Let's look at players making substantially less than Sheed who have been more efficient in similar mpg:
Spencer Hawes (26.4 mpg, 13.84 PER)
Nenad Krstic (23 mpg, 13.86 PER)
Tyler Hansbrough (17.7 mpg, 14.67 PER)
Kris Humphries (17.7 mpg, 14.84 PER)
Taj Gibson (26.6 mpg, 14.26 PER)
Matt Bonner (17.5 mpg, 14.88 PER)
Serge Ibaka (17.6 mpg, 14.43 PER)
Channing Frye (27.1 mpg, 15.15 PER)
Ersan Ilyasova (23.3 mpg, 15.94 PER)
Hakim Warrick (21.3 mpg, 15.88 PER)
Roy Hibbert (2.49 mpg, 15.86 PER)
Chris Andersen (22.5 mpg, 15.92 PER)
JJ Hickson (20.6 mpg, 15.2 PER)
Tyrus Thomas (22.7 mpg, 16.86 PER)
DeJuan Blair (18 mpg, 17.35 PER)
Drew Gooden (24.9 mpg, 17.19 PER)
Robin Lopez (19.3 mpg, 17.7 PER)
Anthony Randolph (22.7 mpg, 18.76 PER)
Your post suggests that people are expecting too much of Rasheed, since he is rightfully a backup. Unfortunately, there are plenty of backup PFs / Cs in this league who make less and are more efficient, which justifies the level of frustration that Celtics fans (and likely Doc) have with Rasheed.