Everyone should understand the limitations of the +/- stat, but they keep track of it for a reason and it is worth considering within the context of other stats and the flow of the game. In other words, use stats to back up or refute what you see on the floor. With that disclaimer, it should be noted that Bill Walker had a big fat negative 21 in his last game. Celtics Hub takes a look at what he did on the floor to get that number:
On the flip side, let’s look at Bill Walker’s 13 minutes of -21 action. The offense produced at least a point on just nine of 22 trips while Walker was on the floor. Aside from a brief OT appearance, almost all of Walker’s playing time came in two stretches, one at the end of the first quarter, and the other at the end of the second.
In the first, Walker was mostly on the floor with other back-ups (Moore, House, Pruitt and Marbury for a small stretch). It’s not a surprise that line-up got outscored.
During the second stint, he got quality time with Pierce, Perkins and Rondo, and the play-by-play shows those three were most responsible for the offensive let down. Perk missed a couple of chippies inside, Pierce went 0-2 with a turnover and Rondo also committed on offensive foul. So maybe Walker’s off the hook here, or maybe his offense is so limited that it makes everything harder for the rest of the team. That’s the beauty and the frustration of plus/minus—it’s hard to reach a definitive conclusion.
Also from CH see one man's opinion on how to handle the rotation for the stretch run.