Not unlike baseball, opening day at the racetrack is a day filled with hope, optimism and excitement. At Suffolk Downs this year, you can add apprehension and trepidation to the list of emotions.Today’s live racing card is the first of 67 scheduled at the East Boston track, and those who make a living at the track are hoping they will not need an impossible dream to make it to 2015.”Opening Day is always exciting,” said Doris Grillo of Saugus, a mutuels clerk who has been working at Suffolk Downs for 18 years. “Everyone is happy to get started.”But …”It is bittersweet this year,” she added. “Everyone is wondering if this is going to be the last opening day we have. We’re nervous, but we’re all excited.”Grillo and her fellow employees know their fate rests with the Massachusetts Gaming Commission, which will award a casino license either to Mohegan Sun in Revere or Wynn Resorts in Everett. If Mohegan gets the license and is able to build adjacent to Suffolk Downs, the track will remain open and likely thrive. If it’s Wynn, Suffolk will almost certainly close.”It’s very frustrating,” said Grillo, whose daughter worked at the track while she was in college. “You would think they would realize this is the best location. We’re next to the airport and the T stops here. It makes sense. But this is Massachusetts.”Trainer Jay Bernardini of Lynn understands what’s at stake, but he remains optimistic that Mohegan Sun will get the casino license and Suffolk Downs will endure.”The outlook is actually more positive than last year,” said Bernardini, who finished second in the trainer standings the last two years. “We had the (referendum) vote hanging over our head last year, and even with it going down in East Boston, the re-vote in Revere and the new possibilities have people feeling positive.”While acknowledging the track’s future comes down to a “50-50 roll of the dice,” Bernardini cannot fathom the Gaming Commission’s effectively putting him and hundreds of others out of business.”Personally, I don’t see how they could go to Everett and lose all the jobs in the Thoroughbred business,” he said. “It’s common sense that if you have a gaming facility that’s been here for 75 years, why wouldn’t that be the ideal spot for a casino?”Bernardini’s situation is a microcosm of the overall situation at Suffolk Downs. He has been running horses there for 25 years. He and his wife, Carol, who works for the TSA at Logan Airport, have been homeowners in Lynn for seven years. Their son Kyle is an eighth-grader at St. Mary’s who is registered for high school there next year. The family is entrenched, yet that will end if Suffolk closes.”I’m a full-time horse trainer,” he said. “It’s a business, not a hobby. If the track closes, I’m leaving, and I’m not the only one who will be in that position. Everything’s not always perfect (at Suffolk Downs), but it’s where we make our living.”Janelle Campbell grew up around the racetrack and worked for trainer Bill Lagorio for nine years before starting a career as a jockey two years ago. You might say she opted for the family business, as her aunt, Tammi (Campbell) Piermarini is the perennial leading rider at Suffolk Downs.”I tried working other jobs, but I hated it,” she said. “I just love working with the horses.”Campbell, a Revere resident, has been an outspoken advocate for the Mohegan Sun proposal, marching in parades, speaking to community groups and anyone else who will listen.”Anything I can do, I’m on board,” said Campbell, a 2003 Amesbury High graduate. “We hope we don’t have to talk about this being our last meet. I keep going like we’re going to keep going. I know that’s what I want.”She’s not alone.Suffolk Downs will kick off its live racing season with a 2:15 p.m. first post today. The track is scheduled to run through Labor Day.