Parker Publication Change

Since debuting his Jesse Stone series in 1997, Robert B. Parker has published new Spenser books every spring and alternated Stone and Sunny Randall books each fall.

Bullets & Beer proprietor Bob Ames posted the following to Spenser's Sneakers last night from Parker's publicist:

There has been a major shakeup in the publishing schedule for [Parker's] books: there is another Spenser novel due on 27 September. The Spenser books will now be published in the fall, with the Jesse Stone and Sunny Randall volumes alternating in March.

I've asked if any reason was given for the change.