Add a power bat
Sluggers like Marcell Ozuna and Nick Castellanos are still available in free agency if the Giants want to make a splashy move to fill some seats. I doubt either signs with the team, but they would unquestionably add some pop to a lineup that will sorely need it.
There have been some reports linking Castellanos with the Giants, but it seems more likely that he will sign with a team like the Texas Rangers that is much closer to contending than the Giants are.
Lower-cost options like Mark Reynolds make more sense. He would be a low-risk acquisition that may have a little something left in his bat, and if not, the team can cut him loose and not be any worse off.
As of now, it seems like Mike Yastrzemski, Evan Longoria, and Brandon Belt will bear the burden of providing the power, so it wouldn’t hurt to give those guys a little help in the run production department.