Martinez, claimed off waivers from the Mets a year ago, hit .237 with six homers and 14 RBIs in 118 at-bats last year for Houston, playing in a career-high 41 games. The 24-year-old Dominican is battling for a starting spot in the Astros' outfield this year, and earlier this week, he backed out of a commitment to play in the World Baseball Classic.
Martinez and the Astros said through a spokesman that they had no comment.
According to documents obtained by ESPN, Martinez's name was listed next to the amount $2,000 and the months February and March. It's unknown what year the documents were referring to.
Several high-profile players have recently been linked via reports to the logbooks of clinic owner Anthony Bosch, including Alex Rodriguez, Melky Cabrera, Ryan Braun and Francisco Cervelli. The now-defunct anti-aging clinic is being investigated by Major League Baseball for allegedly supplying some players with banned substances.
Seth Levinson of ACES sports agency, which represents Martinez, issued a statement to ESPN that denied any knowledge that Juan Carlos Nunez, a former liaison for ACES, has any connections with the clinic as some documents have shown.
"Other than those players who have previously tested positive, we have seen no evidence to conclude that any of the players mentioned recently in the media were involved with performance-enhancing drugs.
"As we've stated unequivocally before: Anyone who knows us, knows that it is absolutely ridiculous to think that we would ever condone the use of performance-enhancing drugs. We have represented many hundreds of players over 25 years, and our track record makes it perfectly clear that we do things the right way. Neither Sam nor I or anyone else at ACES have ever met or even heard of Anthony Bosch until the recent news stories nor does anyone have any knowledge of or connection to Biogenesis.
"Moreover, Juan Nunez ceased doing work on behalf of the agency as soon as we learned of his wrongdoing in the Melky Cabrera matter. The MLBPA's investigation into that matter found that we had no involvement in or knowledge of any wrongdoing. Similarly, in this case, we are not involved and do not have any knowledge as to what took place or who was involved.
"We don't think it is responsible to speculate further given the complete lack of evidence."
Three Major League players whose names appear in Biogenesis records -- Melky Cabrera, Bartolo Colon and Yasmani Grandal -- have been suspended after testing positive for PEDs since last July. MLB can't suspend players without official documents or a failed test.