I'll go to the matt for Martin. I see 3.5-4.5 WAR in his immediate future - based on past performance.
Martin has an impressive minor league record, and a MLB record that approximates, if not surpasses Ackley's, except with stellar glove work in CF, hence the high WAR values. Like you, I chalk up last season to injury, while people a lot smarter than me are looking at their statistic models assuming there was no injury marred season, and assuming for some reason this solid player is regressing rapidly, completely apart from the injury that is staring everyone in the face.
If Ackley played CF like Martin does, we'd probably have swallowed hard and have kept him there for 2016 For the age 27 season. Good pedigrees, late bloomer template. And we'd do this because...He's Dustin Ackley! College hitter of the decade. And he's giving us plus defense in CF. Martin? We treat him like he's dime a dozen. But look at his full body of work.
There are many, many examples of players with Martin's pedigree blooming late and becoming solid, even star, ballplayers.