Nike (NKE - Get Report) can't possibly be too happy with golf phenom Rory Mcllroy.

The number-four-ranked golfer in the world announced Wednesday he would skip the Olympic Games in Rio de Janeiro due to concerns about the Zika virus

"After speaking with those closest to me, I've come to realize that my health, and my family's health, comes before anything else," said McIlroy said in a statement. "Even though the risk of infection from the Zika virus is considered low, it is a risk nonetheless and a risk I am unwilling to take."

Mcllroy is the highest-profile athlete yet to withdraw from the summer Olympics because of Zika concerns, and the decision deals a major blow to the game of golf, which is set to return to the Olympic stage after a 112-year absence.

Mcllroy may have also dealt a blow to his sponsor Nike in the process. The apparel company was poised to have its shirts, golf balls and golf clubs used by McIlroy plastered all over TV screens and social media feeds. 

Nike signed Mcllroy to a reported 10-year, $200 million endorsement deal back in 2013. It represented the most lucrative endorsement deal ever negotiated in golf, likely in large part due to Mcllroy's growing marketability as he gobbles up major championships. With Mcllroy out of the mix at the Olympics, and fellow Nike golf endorser Tiger Woods unlikely to play as a result of a back injury, the footwear and apparel giant will lack a major presence on a very grand stage.

The company's other two athlete endorsers for golf -- Paul Casey and Charl  Schwartzel -- are lesser-known players who may not even appear at the Olympics based on their current world rankings. If they do, each lacks the ability to drive product sales in the same way as Mcllroy and Woods. 

The golf gear marketing edge may end up going to Nike rival Under Armour (UA - Get Report) , whose biggest athlete in the sport -- Jordan Spieth -- is likely to take to the links for the United States. Spieth has said he remains undecided on playing at the Olympics, but did not rule it out completely during an interview at U.S. Open.  

Nike's golf business could have certainly used the shot in the arm provided by a major sporting spectacle like the Olympics. 

Sales for the Nike golf division fell 2% to $771 million for the fiscal year ended May 31, 2015. Excluding the impact of the strong U.S. dollar, sales were unchanged from the prior year. Nike golf, which represents about 3% of the company's overall sales, didn't light up it up on the sales line the year before, either. Nike's golf division saw sales relatively unchanged at $792 million for the fiscal year ended May 31, 2014. Excluding the impact of the strong U.S. dollar, sales rose a meager 1%.