Giants backup catcher Trevor Brown impresses

Giants backup catcher Trevor Brown impresses PHOENIX — The play of backup catcher Trevor Brown has eased the blow of losing Andrew Susac to injuries. In the minors, Brown had seven homers in 1,114 at-bats. “I think it surprises me as much as anybody,” said Brown, adding he has talked with assistant hitting coach Steve Decker about being aggressive at the plate, especially because he gets limited at-bats. Susac has been impressive at the Giants’ Arizona facility and is close to returning to minor-league ball. Brown’s presence has allowed manager Bruce Bochy to rest Posey in a bid to keep the All-Star catcher fresh. Posey has started at catcher in 30 of the Giants’ 40 games and at first base for two more. Conor Gillaspie played third base for Matt Duffy, who rested a tight hamstring but played the final inning. … Reliever Derek Law hasn’t been sharp lately and gave up another run Saturday, and Bochy said the rookie needs to get his pitches down more: “He’s living in the nitro zone right now, so he’s got to make an adjustment there.” The Giants realize Law could be feeling fatigue after recuperating from June 2014 Tommy John surgery. John Shea is a San Francisco Chronicle staff writer. Before Hunter Pence hit his 200th home run Saturday night, the last player to hit No. 200 with the Giants was Marquis Grissom in 2003.