The San Francisco Giants 2019 outfield depth chart currently list Chris Shaw in left field, Steven Duggar in center field, and Austin Slater in right field. All are young players out of the Giants own farm system.
Chris Shaw is a left-handed power hitter who got a little playing time in late 2018 and pretty much showed that he is not ready for the big leagues (as he stuck out 23 times in 54 at bats). Another young right-handed power hitter Mac Williamson spent some time in left in 2018 as did Austin Slater, utility man Alen Hansen, and regular first baseman Brandon Belt.
Center field seems to be the only place where there is somewhat of an incumbent in place in Steven Duggar. Although his 2018 was cut short by an injury, he performed well for a rookie and seems to have the confidence of manager Bruce Bochy not only to start in center field but to bat lead off as well.
Right field currently has Austin Slater listed as the incumbent and he has the combination of speed and arm strength to play there defensively. However, his promising 2017 hitting regressed somewhat in 2018 thus leaving a question mark over right field. Mac Williamson is on the right field depth chart and, although he is not ideal for the position defensively, if he starts to hit home runs this spring like he did last spring the club will most certainly find a place for him.