That certainly is odd. I can't imgaine he called just to say hi. Interesting indeed.
Fitz called Wilson on Sept 29th
http://www.latimes.com/news/printedition/la-na-leak7oct07,1,6072069.story
"However, there was an additional sign that Fitzgerald continued to investigate aggressively. He phoned Wilson on Sept. 29, the same day Miller, the New York Times reporter jailed for refusing to divulge her confidential source, was released from jail after agreeing to testify in the case. She testified the next day."