Oswaldo Arcia left Monday's game with tightness in his upper left back.
Arcia tweaked his back on a big swing-and-miss in the sixth inning and was later removed for a pinch-hitter. The Twins will see how he feels Tuesday, but he might have to miss a day or two.
Michael Morse (oblique) should be ready to return by Friday.
Giants manager Bruce Bochy said that Morse was "tentative" during batting practice Monday, so it will likely take him another couple of days to swing with full intensity. The 32-year-old has been sidelined since late August with a strained left oblique.
Pablo Sandoval is currently dealing with a sore hip.
It was evident throughout Monday's game, though he continued to play and went 2-for-4 with a double. It sounds like something the Giants will attempt to manage, but fantasy owners should keep the situation in mind.
Giants manager Bruce Bochy placed a "pretty good percentage" that Angel Pagan (back) will be in the starting lineup on Tuesday.
Pagan was scratched from Monday's lineup with recurring lower back discomfort. His most recent stiffness dates back to Saturday, but the Giants are optimistic it won't keep him sidelined for long.
Matt Shoemaker will undergo an MRI after leaving Monday's start with a "little" discomfort on the left side of his rib cage.
Shoemaker allowed one run over 7 2/3 innings against the Mariners before exiting. He said after the game that he's not overly concerned, but naturally the Angels aren't going to take any chances.