Continuing the threat that refuses do die but should.....
That^^ is an interesting question.
On the one hand we have JD Martinez who's an average OF'er at best and most of his WAR comes from his offense. In fact, his dWAR has been a consistently negative value. Over the past five years he has a cumulative WAR of 15.9, with over 1/3 of it coming from the career year he's having in 2018.
OTOH we have Jackie Bradley Jr. who's one of the best defensive CF'ers in the AL. However, most of JBJ's WAR has come from his offense (and IMO most people think is an aberration.) His cumulative WAR over the past five years is 12.4.
When we consider the two 5-year WARs and allow for a 17% "variability" We find that JDM's 5-year range of WAR is between 13.2 - 18.6 and JBJ's is between 10.1 - 14.5. Since there is overlap between 13.2 - 14.5 they could be the same player although it's reasonable to assume that JDM is the slightly better player (if you ignore the fact that JBJ's WAR is questionable because of the oWAR/dWAR thing) because his range is higher.
The big equalizer going forward is that JBJ is 28 years old and making $6.100,000 this year and JDM is 31 and making $23.750,000 this year.
So the question is, if you can only keep one of them going forward.... which one do you keep? The younger one who plays better defense or the older one who's offense is better but makes almost 4x as much? And to add yet another wrinkle, if you believe that JBJ has 'found himself' offensively this year what's the REAL difference in their offense? And how much is JBJ's defense REALLY worth? Is it worth almost 4x as much to keep JDM?