Peguero threw two scoreless relief innings in Wednesday's 12-3 win over the Cubs, striking out three.
Peguero retired all six batters he faced, throwing 18 of his 25 pitches for strikes. The right-hander had his contract selected from Triple-A Sacramento last Thursday, when he made his big-league debut. The 28-year-old has tossed three scoreless outings since joining the Giants, allowing four hits and one walk while striking out four across 5.2 innings.