According to the report, Castillo could command a five-year contract worth at least $60 million. He is represented by Jay Z's Roc Nation Sports.
For Castillo to be on a team's playoff roster, he must be signed by Sept. 1.
- Scooby Axson
We've Got Apps Too
Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide - from Peter King, Tom Verducci, Lee Jenkins, Seth Davis, and more - delivered straight to you, along with up-to-the-minute news and live scores.