I don't think Andujar is an upgrade. His defense is worse than Gallo's, he's another righty bat, and he has yet to prove that his bat is as good as it was in 2018. He did not get a ton of playing time this season, but in that limited time he hit .268/.279/.317 (.596 OPS, 73 OPS+). He also had 160+ plate appearances last season and didn't do much better. Compared to Gallo this season who is hitting .173/.285/.346 (.631 OPS, 82 OPS+). Both are pretty bad, but I think Gallo's fielding, power, and left handedness (for whatever it's worth) is what makes him the better play of the two. Hopefully they pick up a better option at the deadline.