Merriman didn't return an email seeking comment but referred to the incident on his verified Twitter account.
"I'm fine guys been working my butt off with training and launching LightsOut and my MBA, flew in from shooting a film in Canada and was...Dehydrated," Merriman posted.
In a later post, he said: "Ok just to clear a few things up b/c certain things are just not cool" and linked a story from a Hollywood gossip Web site in which he was quoted as saying he was dehydrated.
James Brennan, a friend of Merriman's who owns restaurants and nightclubs in San Diego, said he spoke with Merriman on Monday morning and that the former linebacker was OK.
Brennan also said Merriman returned to the club after being treated.
Merriman retired in March after an eight-year NFL career with the Buffalo Bills and San Diego Chargers. Once one of the most-feared NFL linebackers, Merriman's career was slowed by injuries and marred by a four-game steroid suspension in 2006.