From Twitter (Pancakes included):
Those are the only sources so far.Additional info from Pancakes:
McClain_on_NFL John McClain Texans worked out Jeff Garcia in each of the last 2 weeks. He used to play for QB coach Greg Knapp in San Francisco.
If Garcia failed the first two tryouts, then Clemens must be horrid.
UPDATE: Looks like some confirmation coming in:
HoustonTexans Houston Texans The #Texans have placed P Brett Hartmann (left knee) on injured reserve and released QB Kellen Clemens