CHICAGO — Davey Johnson is poised Saturday to take over as manager of the Washington Nationals, replacing Jim Riggleman, who abruptly resigned two days earlier.

It will be Johnson's fifth managerial stop and first since he managed the Dodgers in 2000.

The 68-year-old Johnson managed the Mets, Dodgers, Reds and Orioles over 14 seasons and compiled a 1148-888 record. His 1986 Mets team won the World Series and Johnson's clubs finished first or second 11 times during his 14 previous seasons managing.

DODGERS EXECUTIVE QUITS: Steve Soboroff, hired by Los Angeles Dodgers owner Frank McCourt to oversee improving the fan experience at the stadium, has resigned after two months on the job.

Team spokesman Josh Rawitch said Soboroff quit Saturday in a resignation letter to McCourt, citing Major League Baseball's oversight of the team as the reason.

In his letter, Soboroff wrote that "an unanticipated action by the commissioner of Major League Baseball resulted (understandably) in elevating the resolution of 'control and ownership' issues to top priority, as it remains to this day. As a consequence, it is not possible for me to effectively work on the very initiatives and contributions that you had hired me to implement."

OSWALT INJURED: Phillies right-hander Roy Oswalt has a mild bulging disc in his back and likely won't return until August.

Oswalt was placed on the 15-day disabled list Friday. He is 4-6 with a 3.79 ERA in 13 games. The three-time All-Star is 1-5 with a 4.06 ERA over his last eight starts

Team doctor Michael Ciccotti says Oswalt will get a second opinion from a specialist in Dallas and then receive a treatment plan.

Oswalt says doctors told him eventually he'll need back surgery, but he hopes that will come later in life. Oswalt says he spent more time in his last two starts worrying about blowing out his back than his pitching.

He does believe he can return for the final two months of the season.

Oswalt lasted just two innings in the Phillies' 12-2 loss to St. Louis on Thursday night.