Baseball It's been almost 20 years since Major League Baseball last expanded. That might change soon."I'm open to the idea,"  commissioner Rob Manfred said Tuesday. MORE: All-Star Game photos | Best All-Star Game performances | Manfred mulls expansionManfred, speaking with reporters in advance of the 2015 All-Star Game in Cincinnati, shared his vision for baseball's future, which includes the possibility of expanding for the first time since it birthed the Diamondbacks and Rays in 1998. Manfred said the league has compiled a list of potential markets that could be viable options for expansion. "Maybe one of the reasons I got this job is, I'm bullish on this game," Manfred said. "I think we are a growth business, broadly defined. And over an extended period of time, growth businesses look to get bigger. So yeah, I'm open to the idea that there will be a point in time where expansion may be possible."With uncertain stadium situations in Oakland and Tampa, relocation could be another option. Though Manfred said he's optimistic the Rays and Athletics will be able to earn favorable stadium deals from their respective cities, there are other markets that have expressed interest in a team and would make for leverage in the league's favor.Montreal, Charlotte, N.C., San Antonio, Portland, Ore., Las Vegas, Oklahoma City, and Mexico City, Mexico, are believed t

o be some of the markets on 's radar to be awarded a new or relocated franchise.MORE: 's awful All-Star hatsAs it stands now, Montreal figures to be on any short list. The city's mayor, Denis Coderre, has been especially vocal about luring a team and met with Manfred in New York in late May to begin discussions.Montreal, which hosted the Expos from 1977-2004, is pining for the return of baseball, as evidenced by its 96,000-fan attendance for two exhibition games between the Blue Jays and Reds in March.But Manfred has been adamant the city requires a new stadium before it's considered -ready."It's a long way from two exhibition games to 81 home games in a facility consistent with major league standards," he said.