I still like MAT. Hits better and plays better defense. Fast...might be a smarter base-runner. Yes, Taylor's hitting has fallen back to about .275 and .800 OPS, roughly his good 2017 season. For now, Stevenson should start.
Thinking back, I don't remember that Robles fought for and won the starting CF job. My memory -- not entirely trustworthy -- is that Robles was given the starting job.