I can't recall the name of the episode, but CSI ran one that had been originally written as a Grissom lead but when there was a death in William Petersen's family, it was hastily rewritten for Nick Stokes.Which is why the first couple eps of the 'new' replacement character are weird They basically get the lines the departed actor had.
Worked out really well.
LaSquisita
"Gum Drops". Should have been Nick's from the start due to the plot line. Turned out to be one of the best episodes ever, in my admittedly biased opinion.