Mark Leiter Jr. had no time to get comfortable in his bullpen chair Saturday.
Leiter was summoned after Cubs starter Alec Mills departed after only two batters because of tightness in his lower back, but he pitched with ease, limiting the Red Sox to three hits in 5u2153 innings as the Cubs earned a 3-1 victory that extended their winning streak to four games.
‘‘Big-time performance,’’ manager David Ross said after Leiter preserved most of the bullpen.
Leiter, who has shuttled between Triple-A Iowa and the Cubs this season, stranded Rafael Devers at second in the first and retired 13 of the first 15 batters he faced.