SAN FRANCISCO — With his second single on Tuesday night, Daniel Susac became the first Giant since at least 1900 to record a base hit in his first five career at-bats. The record books for that kind of feat don’t go any deeper than that, but you don’t need to look too far back for a reminder of why teams don’t often overreact to early results. The current Giants regime might know that better than anyone. At the start of the season, they DFA’d outfielder Luis Matos, who won an NL Player of the Week award as a 22-year-old. A few days later, they parted ways with Tyler Fitzgerald, who briefly turned into Barry Bonds as a rookie. There are stories like Susac in MLB every year, although his start is certainly hotter than most, and there are good reasons to think the talent is not a mirage. The 24-year-old was the 19th pick in the draft in 2022 and hit .280 in the minors. While the A’s, who left him unprotected for the Rule 5 Draft, felt his Triple-A numbers were a bit inflated by a hitter-friendly environment in Las Vegas, Susac spent the offseason doing drills to fill the gaps in his approach. Susac’s dad, who raised two...