"It is hard to imagine right now having gone through what we did as an industry, and the testing that's in place, to think you'd be able to circumvent that somehow seems almost impossible," Chicago manager Joe Maddon said. "It's surprising. I don't really know [Gordon]. I know that he's really good and I know the difference he made for that team."
Zobrist said players trust a lot of people who take care of them to protect them from taking anything that could result in a positive test.
"It's a little upsetting when you stop and think about it, especially when it happens during the season," Zobrist said. "You roll your eyes for a minute. It's going to continue to happen and people will keep trying to find a way around the hard work and everything that goes into the hard work in this game. It's just the nature of man, I believe. People are always going to try to find a way to cheat the system. It's up to us as players to do the best we can to keep other guys from doing that."
Zobrist said he is in favor of even tougher rules to penalize players who take illegal substances.
"I am, and I think most players are," Zobrist said.
Gordon issued a statement saying he didn't realize he was taking something that was tainted.
"Personally, everything I take I make sure it has that NSF symbol on it, which is supposed to protect us," Zobrist said of the National Sanitation Foundation certification. "I don't know if you can taint food or drink where someone else could put something in. It's possible, I assume. That's what makes it a little bit scary. I guess that's why you have to be really careful and trust who's giving you what you put in your body. Most of the time, we trust what's set in front of us."
Athletic trainers provide lists of approved supplements and vitamins. If players are going to an outside source, they're taking a risk, Zobrist said.
Said Jason Heyward: "It's kind of scary knowing you have to be that careful."
Carrie Muskat has covered the Cubs since 1987, and for MLB.com since 2001. She writes a blog, Muskat Ramblings. You can follow her on Twitter @CarrieMuskat and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.