Bryce Harper of the Nationals and Manny Machado of the Orioles are young, controlled superstars who look like highly appealing extension targets. Of course, that also makes them incredibly expensive potential candidates for their respective teams, as Jon Heyman explains at todaysknuckleball.com. According to Heyman, there’s some suggestion that it could take more than $500MM over an unprecedented term to keep Harper from heading to the open market after the 2018 season. “We have not to this point had any substantive negotiations about a long-term deal,” Nats GM Mike Rizzo said with regard to Harper. Rizzo did suggest that the team has serious interest in doing so, however. “They know what our intentions are,” he said. “My intention is always to get him on a long-term deal that will make him a National for life. At a very young age he performed admirably, not only admirably, but the year he had was historic. It’s going to be a unique deal. We have a very unique player.”

As for Machado, he might not be far behind in value if the O’s hope to reach a deal. Intriguingly, the report suggests that Baltimore very nearly agreed to a seven-year contract with its best player at some point in recent years. That would have certainly proved a bargain given Machado’s increasingly outstanding performance, though the terms of the prospective pact are not known. (Neither is it clear what caused negotiations to fall apart.)

Here’s more from Heyman: