NEW YORK -- The Rockies reinstated Carlos Gonzalez from the bereavement list on Wednesday and optioned reliever Guillermo Moscoso to Triple-A Colorado Springs.

Moscoso delivered 2 1/3 scoreless innings on Monday against the Mets, but his ERA stands at 7.53. He gave up eight earned runs in 1 2/3 innings on July 26 against the Nationals.

On Monday, Moscoso pitched in place of Josh Roenicke -- normally a member of Colorado's piggyback crew of extended relievers. Roenicke has logged 73 1/3 innings in 2012 -- more than his last three seasons combined -- and is being used in smaller doses to help rest his arm.

Manager Jim Tracy said Moscoso will rejoin the team as a September callup.

"We're very mindful of where [Roenicke] is at from an innings standpoint, which goes back to Moscoso and a lot of the reason as to why he'll return to our club in early September," Tracy said.

Tulo, Giambi begin rehab assignments Friday

NEW YORK -- The Rockies announced on Wednesday that Troy Tulowitzki and Jason Giambi will begin rehab assignments with Double-A Tulsa on Friday. Neither are expected to rejoin Colorado until next month.

Tulowitzki traveled to Philadelphia on Wednesday to meet with the same doctor who performed surgery on his groin on June 21 -- the shortstop has been out since May 30 with the injury. A positive report and a healthy feeling Tulowitzki gave the green light to begin the assignment on Friday.

"It's been a long process and it's been frustrating," Tulowitzki said of his recovery. "I've watched a lot of games that we haven't played particularly well, but I've also seen a lot of positives. I've seen a lot of young guys on the field that have played real well and I'm excited to get on the field with them."

Tulowitzki is scheduled to play five innings on Friday, followed by a day off to ease him back into everyday play.

"It's going to be mixed emotions for me when I get out there playing," he said. "I'll be nervous, I'll be excited, but I just want to get through a game to prove I can do everything and we'll take it from there."

Giambi, meanwhile, will play a complete game on Friday as DH. He has been on the disabled list since July 24 with a viral infection.

Advanced instant replay gets mixed reviews

NEW YORK -- Major League Baseball's testing of two advanced instant-replay systems at Citi Field for Colorado's four-game set again the Mets has drawn mixed reactions in the Rockies' clubhouse.

"In fairness to the outcome of the game, you completely understand it," manager Jim Tracy said. "But I think more than likely, one of the things they need to sort out is how long can you leave a pitcher standing there while you sort out all of these different situations."

The systems -- one uses cameras and the other radars -- are used to review close balls down the foul lines. But much like recently implemented home run reviews, the idea has taken a lot of heat.

"The biggest concern for me would be that guy standing on the mound," Tracy said. "How long do you leave him standing there and how does it interrupt the even flow of the game?"

Reliever Matt Reynolds was on the same page as his manager.

"Anytime you're warmed up and there's a stoppage in play, that would be the biggest downfall," he said. "I feel like there could be a system that could make it instantaneous, maybe someone up in a booth looking over replays. That way if there was a challenge, umpires wouldn't have to leave the field."

That stoppage in play may have more of an effect on relievers than starting pitchers. Starter Alex White said that gaps in play are part of a typical outing and that making the right calls should be the main concern.

"It's not really a big deal," White said. "I think we just want to get the calls right and if they need replay to check home runs and foul balls, then it doesn't bother me one bit.

"If a guy hits a ball that's questionable, you want to know and make sure that they got it right. The time it takes to do that is certainly worth it."

Worth noting

• Tracy said that he will not lift the 75-pitch limit placed on his starters despite Jhoulys Chacin's return from the diabled list. Colorado is -- at least temporarily -- back to a five-man rotation.