The Giants had hoped Johnny Cueto would be able to rejoin the rotation this weekend in LA.
But back tightness during a bullpen session delayed Cueto's return.
Instead, Cueto will make his 2019 debut on Tuesday at Oracle Park against the Pittsburgh Pirates.
Johnny Cueto starts Tuesday at Oracle Park. So it's Bumgarner and then Cueto at start of homestand.— Alex Pavlovic (@PavlovicNBCS) September 8, 2019
Tuesday's start will be Cueto's first major league start since he underwent Tommy John surgery last year.
In two rehab starts with Triple-A Sacramento, Cueto allowed three earned runs in 10 1/3 innings and struck out nine batters.
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Rookie Logan Webb was the scheduled starter on Tuesday, but he will be pushed back. The Giants didn't immediately announce how the rotation will unfold after Cueto's start on Tuesday.