According to MLBTradeRumors via Geoff Baker the Pirates and Mariners are discussing trading Jack for Yuniesky Betancourt. Jack is FAR better defensively as is covered in the article. The reason it seems to me that the Pirates would consider this is Betancourt is signed through 2011 for roughly $10.5 million including his $2 million buyout in 2012, so we would basically have him to bridge the gap at a reasonable price to whoever our real future SS is, as it looks like there would be nobody to replace Jack next year. If he were to turn things around and/ or move to 2B I doubt we would buy out 2012.
The two are similar offensively, but if you want to play Devil's/ Betancourt's Advocate you could say Jack is on his way down while Betancourt is younger and playing in a notorious pitchers park at SafeCo.