PHOENIX -- Joe Saunders underwent treatment on his ailing left hip on Wednesday, one day after tossing six innings against the Rockies.

Saunders began to feel soreness in the hip following his April 27 start against the Phillies.

"It's feeling better since the treatment," Saunders said. "Hopefully, it's a non-issue."

Saunders' next scheduled start is on Sunday, in San Diego.

"I think so," he said when asked if he would be able to pitch.

Blum could start rehab in four weeks

PHOENIX -- Geoff Blum was greeted warmly by his teammates when he returned to Chase Field on Wednesday for the first time since undergoing arthroscopic surgery on his right knee on April 26.

There was some concern that Blum might need microfracture surgery, a more serious form that would have kept him out for six to nine months.

"When they got in there, it was actually better than the MRI showed," Blum said. "There was more cartilage in there. Other than not having to have any surgery, this was the best-case scenario."

Blum, who has been out of action since early in Spring Training, should be able to start a rehab assignment in four or five weeks.

"I was extremely relieved," he said. "It already feels better than it did before the surgery, so I'm happy about that."

Heilman, Duke take steps forward

PHOENIX -- A pair of D-backs pitchers took steps forward on Wednesday.

Reliever Aaron Heilman (shoulder) threw 15 pitches in an extended spring game on the back fields at Salt River Fields.

Manager Kirk Gibson, who watched the performance, said that Heilman threw well and, if things continue to progress, could be activated on Friday.

Meanwhile, starter Zach Duke (broken hand) threw a 40-pitch batting-practice session. The lefty threw 20 pitches, sat down to simulate an inning break, then threw 20 more.

"I felt a little too strong, I jerked a couple of balls," Duke said. "The hand feels great, the arm feels good, my body feels good. It's the first hitters I've seen in seven weeks."

Duke will throw a bullpen session on Friday and then two innings on Monday in an extended spring game. Gibson wants Duke to throw close to 100 pitches in a Minor League rehab start before activating him.

It will take a while for Duke to build up to that.

"It's almost like starting Spring Training over again," Duke said.

Drew a late scratch from Wednesday's lineup

PHOENIX -- Shortstop Stephen Drew was scratched from the starting lineup on Wednesday for "precautionary reasons."

Drew has been experiencing some tightness in his right groin, and has also been battling a case of the flu.

"It's day to day at this point," Drew said.

Drew did not start in the first five games of the year because of an abdominal strain, but since then had started 23 straight games before Wednesday.

Josh Wilson started at short in place of Drew, who leads the team with 22 RBIs.