D.Lee left today's blow-out of the Pirates in the 6th inning with a stiff neck. Of course, Daryle Ward hit a home run in his absence, so their was a silver lining. Having Ward heating up could be a key to some late inning match-ups.
You may recall Derrek having neck issues in the past. He missed several games in May of 2007. Going back to 2005, he missed time in Spring Training.
If Lee can't play, Matt Murton probably moves into the line-up. Mark DeRosa would be a likely choice to play first against tomorrow's lefty starter, finally vacating left field.
On the other hand, I figured Murton would be called up as soon as Alfonso Soriano got hurt, and I figured he'd start against Tom Gorzelanny. So, he may still sit against Zach Duke.
Derrek may be ready and willing to start tomorrow, but will only play if Lou lets him. With the Mets coming in and a trip to Colorado coming up, it might be a reasonable time too look ahead a few days, and be cautious now.