White Sox activate LHP Aaron Bummer from IL

The Chicago White Sox reinstated reliever Aaron Bummer from the 10-day injured list and recalled right-hander Reynaldo López from Triple-A Charlotte on Friday.

The AL Central leaders also optioned relievers Matt Foster and Jace Fry to their top farm club.

Bummer, 27, had been sidelined by a strained right hamstring. The left-hander is 1-4 with a 3.26 ERA and two saves in 32 games heading into Friday night’s series opener against Houston.

López has been working as a starting pitcher, but he will work out of the bullpen with Chicago. The 27-year-old right-hander made five relief appearances in his first 92 big league games.

López went 1-3 with a 6.49 ERA in eight starts with the White Sox last year. He spent the first part of this season with Charlotte, going 1-6 with a 7.62 ERA in 10 starts.

"He earned a spot. His velocity is up, making a lot of good pitches," manager Tony La Russa said, "and he gives us some length in the bullpen."

La Russa also said López could start one of the games in Monday’s doubleheader against Minnesota.

The White Sox also announced that veteran utilityman Jake Lamb is going to Charlotte to begin a rehab assignment. Lamb, 30, is coming back from a strained right quadriceps.

Foster, 26, was a key part of Chicago’s bullpen last season as a rookie, but he has struggled this year. The right-hander is 2-1 with a 6.15 ERA in 26 games.

The 28-year-old Fry opened this season on the IL after he had an offseason microdiscectomy. He made two appearances with the White Sox, allowing three runs in two innings.