CHICAGO -- Brandon Webb was back on the mound Friday.

OK, so he wasn't throwing a baseball, but the right-hander was simulating his motion with a towel in his hand, which pitchers do when they want to do mound work without actually throwing.

For Webb, the towel drill has value because it's been so long since he's thrown off a mound that getting comfortable on one again is a challenge in itself.

"It just helps me to get the feel of the slope of the mound," Webb said. "That's the biggest thing in going from flat ground to the mound. This should help."

So when does Webb think he'll be throwing a ball off the mound again?

"Maybe in a week and a half," he said. "I'm up to throwing three days in a row now."

Webb, who had shoulder surgery in August, has not thrown off a mound since March 4 and last pitched in a big league game on Opening Day 2009.

Good news for injured Benson, Jackson

CHICAGO -- An MRI of Kris Benson's right shoulder showed no structural damage, and he could start throwing as soon as next week.

Benson was forced to leave Wednesday's game with discomfort in his shoulder and pectoral muscle area. The veteran has had shoulder problems in the past, but this appears to be just a strain. Once the inflammation calms down, Benson will begin playing catch again.

The news was not as good on reliever Leo Rosales' right ankle.

Although they are still waiting for the results of a CT scan, D-backs manager A.J. Hinch said it looks like a "fairly significant foot sprain."

Hinch added that the way it looks now, Rosales will be out longer than Benson. Both were placed on the 15-day disabled list Thursday.

Outfielder Conor Jackson (right hamstring) took batting practice on the field for the second straight day and is getting closer to leaving on a Minor League rehab assignment.

Jackson is eligible to come off the DL on Tuesday, but the team wants to both make sure he is 100 percent by having him play three or four Minor League games, so he may not be activated until a little later.

Grace flattered to lead stretch at Wrigley

CHICAGO -- Mark Grace has done it twice before, but come Sunday he still figures to have some butterflies in his stomach.

The D-backs broadcaster, and former Cubs star, will lead the crowd in "Take Me Out to the Ball Game" during Sunday's seventh-inning stretch at Wrigley Field.

"It's nerve-racking," Grace said.

Hall of Fame broadcaster Harry Caray started the tradition, and the Cubs have kept it up as a way to honor him since his death in 1998 by inviting former players and celebrities to do it.

Grace's first two renditions of the song were not without controversy.

"I've done it twice before, and I've said both times, 'Root root root for the Cubbies,'" Grace said. "I know that some of our loyal followers weren't happy with that, and I understand that. But it's a tribute to Harry Caray, so let's not lose sight of that, and that's the way he sang it."

Grace played 13 years with the Cubs from 1988-2000 and was a fan favorite. His parting after the 2000 season was acrimonious, but he has since buried the hatchet with his former club.

"That they think enough of me to ask is certainly flattering," Grace said.

Snyder offers his own analysis of Cubs' lineup

CHICAGO -- Chris Snyder walked out of the video room Tuesday in the visitors' clubhouse at Coors Field, with a piece of paper in hand and presented it to pitching coach Mel Stottlemyre Jr.

"Here you go," Snyder said.

Snyder had filled the entire unlined sheet with notes about each of the Cubs hitters the D-backs were slated to face in a couple of days.

"Breaking them down, trying to see what they do in different counts," Snyder said. "It's just a general overview. The big thing is you feel prepared when you put the time in like that. You have more conviction, and you're not second-guessing everything."

The D-backs internally put together scouting reports on upcoming opponents, and Stottlemyre will do his own as well, but he likes to have Snyder's input.

"It's just a way to make sure we're all on the same page," Stottlemyre said. "He comes up with some good stuff."