Anthony Spencer's situation is said to be nearing a point where he's capable of offering at least parttime help in providing a pass rush if and when called upon. The staff sees his progress on a daily basis and should be in an ideal position to know. It should be of interest to see if and when he'll have arrived at a point where he is capable of practicing with the rest of his teammates. That is usually a revealing indication as to whether or not he is nearing that point. There's also the question if situational help is enough for him to be awarded an active roster spot. That will be an interesting decision to be forthcoming in the weeks to come.
In a similar situation, Rolando McClain's conditioning, by his own estimation, is not yet where it needs to be for him to merit a starting job. In a very recent post, Bryan Broaddus made exactly the same assertion, saying he's not yet capable of playing four quarters of NFL football. Understand that this is not to say he can't or won't arrive at that point sometime in the forseeable future. Nevertheless, it isn't yet the case. Let's consider this comes from someone who has earned a living making such evaluations.