Galvis, 28, hit just .255/.309/.382, with 80 wRC+, 29 doubles, six triples, 12 home runs and 14 stolen bases in 2017 for the Phillies. He was a poor defender with -5 DRS, but did have a 3.5 UZR/150. For his career, Galvis has -10 DRS in 4276 innings at shortstop.
The switch-hitting Galvis has slashed an underwhelming .245/.287/.372 with a 75 wRC+ during his six seasons with the Phillies. His numbers are even worse away from Citizens Bank Park with an .628 OPS on the road.
The Phillies receive Santos, who was the Padres No. 13 prospect according to MLB Pipeline. The 21-year-old is coming off a solid season in Double-A with a 3.78 ERA, 1.19 WHIP and 138 strikeouts compared to only 48 walks in 150 innings.
Galvis is under team control for one season. The Padres had shown interest in Zack Cozart before finalizing this trade.