When Jose Fernandez was lost to a ligament tear in his right elbow, the Marlins opted to call up right-hander Anthony DeSclafani from Jacksonville. Heaney was considered, but the fact that he threw seven innings a few days ago eliminated the chance of him pitching on Wednesday at Los Angeles.
The Marlins also signed veteran Randy Wolf, which eases the urgency to rush Heaney.
Still, the young lefty, who turns 23 on June 5, is inching closer to making his Major League debut.
"He was definitely in consideration, as was Brian Flynn [from Triple-A New Orleans]," said Michael Hill, president of baseball operations. "We looked at all of our upper-level pitching. When we got the news [about Fernandez], we really couldn't reshift rotations to make someone available."
Another candidate at New Orleans who could be viable in a month or so is lefty Adam Conley, but he is returning after a bout of inflammation in his left forearm and only resumed his throwing program on Tuesday.
"It was more muscle," Hill said. "It was not ligament involvement. When he is stretched out, he will be back in the rotation."
As for Heaney, he continues to impress and improve his overall game, meaning holding runners and fielding his position.
"He's making steady progress," Hill said. "It's really just a matter of giving him innings before he is ready to go. Similar to DeSclafani. I think they're both Major League starting pitchers. It's just a matter of when they become Major League starting pitchers."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter