Sources on location tell us that someone picked up his bib before the Boston Marathon.
in summary:
TIME COURSE on Dr. KL
# of road races completed in year 2010: ~20.
with last road race - 12/10/2010
------------------------------
--------------
Date LetsRun thread allowed to continue,StudyOf KL blog started, etc. - 1/6/2011
------------------------------
# of road races completed in 2011: 0. (DNS at CowTown in Feb)
------------------------------
Today's 2012 Boston Marathon DNS - 4/16/2012