With three weeks until the Opening Day, it’s time to start talking dominoes. And not the cool ones that make the world’s biggest figure eight en route to a spot in Guinness. We’re talking about bad dominoes, like the ones teetering at David Ortiz’s locker before spidering to every corner of the Red Sox clubhouse. Simply put, the Sox have an Ortiz problem, and neither the team nor the DH has any idea how it will be resolved. The best-case scenario is that Ortiz’s injured Achilles’ stops hurting, he sprints without a care in the world, and the Red Sox ride his All-Star production deep into the heart of the pennant race. That scenario seems less likely by the day, however. Ortiz, who takes great pride in not only the place he holds in the lineup, but in his ability to fill it, appears genuinely concerned. The pain appears every time he runs. The season is fast approaching. After six months of this, he’s having a hard time staying positive. Those who’ve been around Ortiz for the last decade need only take one look at him to realize something’s wrong. The outgoing personality and larger-than-life clubhouse presence appear intermittently, but in small enough doses to serve as a reminder of what’s missing. The clock is ticking, and the Red Sox will soon need to seriously consider Plan B.