Defensive numbers aren't typically the most reliable, just hard to measure... but Grichuk is SLIGHTLY below average by the numbers. The eye test tells me that he's a good RF and passable CF.
Interestingly, last year the numbers showed that Teo was a positive fielder in LF, and also slightly below average in CF. Eye test suggests he's worse than Grichuk at both corners and CF (with the exception of his arm, which is positively Bautistian).
LGJ also is slightly below average by the numbers in LF (but just f***ing awful in the infield, though that's heavily skewed by whatever brain farts he was having this year at 2B)
Looking at extremely small sample sizes, The numbers show that Fisher is good/excellent in the corners and ghastly in CF, same for Alford. Alford, however, wins the eye test, though I am unabashedly #teamAlford (yes, still.)