Houston Astros superstar Justin Verlander is currently a free agent. Many expect him to return to the team he has won two World Series rings with. Some even expected him to have already signed by now.

However, the soon-to-be 40-year-old is still on the market, free to sign anywhere. One has to wonder why Verlander is still unsigned. Ken Rosenthal of The Athletic recently provided a potential answer.

“It has not happened, perhaps because Verlander sees the potential for lucrative opportunities with the Mets, Yankees and Dodgers, among others,” Rosenthal wrote in a recent piece.

The Astros certainly will face steep competition from other teams around the league. The three teams mentioned by Rosenthal specifically have shown little hesitation spending big in free agency in recent years.

Perhaps the New York Mets have a leg up over the other two teams. Not only do they have deep pockets, but there's a sense of familiarity for Verlander there. Max Scherzer is on the Mets, and the two played together with the Detroit Tigers from 2010-2014.

Speaking of the Tigers, they represent a potentially lucrative opportunity for Verlander. They have the payroll flexibility to re-acquire the franchise icon after trading him to the Astros in 2017. Given where Detroit is in their rebuild, however, it seems unlikely.

Rosenthal also notes one other potential reason Verlander has not resigned. Last offseason, the future Hall of Famer negotiated his deal with general manager James Click. The Astros fired Click shortly after winning the World Series earlier this month.

Verlander's value is set to rise later this week, as he will likely win his third American League Cy Young Award. Only time will tell if the Astros pay up to keep their future Hall of Fame ace.