Cueto, 27, will replace southpaw Tony Cingrani in the bullpen. Cingrani left last Tuesday's start with back spams, but Thursday's off-day allowed the team to rearrange the rotation and push his spot back to Monday.
Between injuries, Cueto went 4-2 with a 3.33 ERA in 48 2/3 innings. He'll join the formidable rotation quartet of Mat Latos, Homer Bailey, Bronson Arroyo and Mike Leake.
Cueto recently said he was willing to pitch out of the bullpen if that's where the team needed him the most. Cingrani pitched in relief earlier this year.