DENVER -- Nationals catcher Ivan Rodriguez has experienced a setback in his recovery from a strained right oblique and will not begin a Minor League rehab assignment over the weekend, manager Davey Johnson said on Thursday.

Rodriguez will visit Dr. Bill Meyers in Philadelphia for a second opinion. Meyers is the same doctor who performed surgery on Ryan Zimmerman's torn abdominal muscle in May.

It is not yet known whether Rodriguez's injury will require surgery.

"They just want another opinion," Johnson said.

Rodriguez, who has been on the disabled list since July 7, was expected start a rehab assignment over the weekend with Class A Hagerstown, but that has been scratched for now.

"I know how anxious Pudge is to get back out here," Johnson said. "I'm sure he's been pushing it, and I'm sure he's been aggravating [his injury] by pushing it."

In 39 games as a backup catcher, Rodriguez is hitting .214 with two home runs and 19 RBIs.

Strasburg set to return to mound Sunday

DENVER -- The Nationals made it official: Stephen Strasburg is scheduled to make his first rehab appearance on Sunday with Class A Hagerstown.

Strasburg threw a successful side session Thursday, two days after pitching in a simulated game in Viera, Fla.

Strasburg, who is recovering from September Tommy John surgery, is scheduled to pitch one or two innings in the first of what is expected to be four rehab starts, setting him up for a return to the Major League rotation in September.

The No. 1 overall pick in the 2009 First-Year Player Draft was 5-3 with a 2.91 ERA over 12 starts last season.

Nationals' Johnson reflects on Stairs' career

DENVER -- Davey Johnson didn't manage Matt Stairs for long, but the former Washington first baseman, who announced his retirement from baseball on Wednesday, left an impression nonetheless.

Though feeling under the weather on Thursday, Johnson took time to reflect on the career of Stairs, who played in 56 games for the Nationals in a reserve role this season.

"He had a good, long career," Johnson said. "He was very well-liked and respected around here."

Stairs' charisma and positive influence in the clubhouse leads Johnson to believe the former slugger will be successful in his next endeavor.

"I heard he's coaching a [hockey] team," Johnson said. "I'm sure he'll be good at that."

During his 19-year Major League career, Stairs hit .262 with 262 home runs and 899 RBIs.