Ravenstahl attempting to establish performance? or loyalty?

Michael Hasch at the Trib is reporting, "Mayor asks for several directors’ resignations". This comes after making a few high-level changes in his administration last month. The mayor stated:

"All directors are admirable colleagues of mine who have been working very hard," Ravenstahl said in a statement.
"However, I am not satisfied with the condition of city government. As mayor, I owe it to the people of Pittsburgh to build our government with the best people who are capable of doing the best job."

Joanna Doven, the interim spokesperson for the mayor said:

"It doesn't mean they are going to be fired. The mayor wants to make sure they are the best people for the position, and he's encouraged all of the directors to apply."

So, the mayor asks all these dept heads for their resignation letters but tells them to apply for their job back? That they can serve until they are replaced? That a national search will begin immediately for the best talent?

In organizations and companies I am familiar with, one reviews the job performance of an individual against the responsibilities and goals of that position to see how that individual adds up. You don't ask for resignation letters and then review their application for their job.

How does this benefit the Ravenstahl administration? I'd bet it will motivate some lazy department heads (if any are, in fact, lazy) but, moreso, it will shore up which department heads are loyal to this mayor.

And I'd bet that that Zober had something to do with the resignation letter approach. Remember last summer? Zober was at the center of all of it - and, in the past, has been known to prepare resignation letters for people to sign.

The whole move smells fishy if you ask me.

UPDATE
The PG reports the mayor said that "he felt it was time to put his mark on his administration by making his own selections for department heads". The PG also notes that under the city's home rule charter, Mr. Ravenstahl has 90 days to fill the positions. Let's see what will happen by Sept. 15th.

WPXI, though, notes that the mayor is calling for the City Solicitor and EMS Department head to resign.

Don't know how I missed this, but some good discussion about the events in the comments section.