Samir Nasri will have to explain the intravenous drip treatment he is said to have received at a Los Angeles clinic amid concerns he may have violated anti-doping rules.
The Spanish Agency for Health Protection in Sport (AEPSAD), which handles doping issues in sport, said on Wednesday it was launching an investigation.
The French playmaker is currently on loan from Manchester City to Spanish side Sevilla.
AEPSAD stated on its official Twitter feed: "AEPSAD has initiated the appropriate steps to clarify what treatment was received by the player Samir Nasri."
According to the Drip Doctors clinic, Nasri received its 'Immunity IV Drip'. The clinic states that the treatment involves one litre of hydration, and is designed to "combat superbugs and common viruses".
However World Anti-Doping Agency rules state that there is a 50 millilitre limit for active athletes.
WADA's prohibited list includes: "Intravenous infusions and/or injections of more than 50ml per 6 hour period except for those legitimately received in the course of hospital admissions, surgical procedures or clinical investigations."
Nasri is due to return to Spain this week after spending part of the La Liga winter break in the United States.
Drip Doctors refused to comment when contacted by Press Association Sport on Wednesday.
Manchester City referred enquires on the situation regarding their player to Sevilla.
A spokesman for the Spanish club said Sevilla had no information beyond what had been reported in the media.
News of Nasri's treatment emerged on Tuesday evening.
Drip Doctors posted a message and photograph of Nasri alongside the organisation's co-founder Jamila Sozahdah on the Twitter feed @DripDoctors, which read: "We provided @SamNasri19 a concierge Immunity IV Drip to keep him hydrated & in top health during his busy soccer season with @SevillaFC"
Nasri's official account subsequently quoted the @DripDoctors Twitter posts, which were then followed by a series of bizarre and sexually explicit messages.
Safe to say Samir Nasri has had an...interesting night. pic.twitter.com/6EZXED5uhE— We Are Football (@WeAreFootballGB) December 27, 2016
The string of posts was later deleted, and Nasri stated: "My account got hacked sorry about what happen earlier."
My account got hacked sorry about what happen earlier— Samir Nasri Official (@SamNasri19) December 28, 2016
The World Anti-Doping Agency (WADA) and the Spanish authorities had been alerted to the claim about the clinic visit by a Twitter post from Richard Ings, the former head of anti-doping at the Association of Tennis Professionals (ATP), who also worked as chair and chief executive of the Australian Sports Anti-Doping Agency.
He quoted the post from @DripDoctors, adding on his Twitter account @ringsau: "Which should be of great interest to @wada_ama and @AEPSAD #IV>50mlbanned"