The Cubs will receive compensation if either of the free agent pitchers leave.
The Chicago Cubs extended $17.4 million qualifying offers to pitchers Jake Arrieta and Wade Davis. Both pitchers have ten days to decide whether to accept the one-year deal or become free agents. Both players are expected to decline the offer and test the market.
The rules about qualifying offers have changed this year, and you can read about the changes here. The compensation the Cubs will receive if either player leaves is based on whether or not they exceeded the luxury tax threshold in 2017. The Cubs did pay the luxury tax in 2016, but the threshold was raised with the new collective bargaining agreement and I believe that Cubs stayed under that in 2017, despite a higher payroll this year. Those figures are not officially announced for 2017 until December. But assuming that the Cubs are under, they will receive a draft pick at the end of the second round, after the small market teams pick.
Source:: Bleed Cubbie Blue