PHOENIX -- Even though Rockies catcher Wilin Rosario wasn't in the lineup Monday for the third consecutive day, his absence was due more to who was on the mound, not because of his injured ankle.

Manager Jim Tracy said he didn't want the 23-year-old, who left Friday night's game after awkwardly twisting his left ankle, to return to game action with newly acquired Jonathan Sanchez pitching.

"I just wanted Ramon Hernandez to catch Jonathan tonight, just because [Rosario] might've had to react to some pitches that are thrown errantly," Tracy said. "And from what I was telling you guys yesterday, he still is having trouble pushing to his right. I don't want to put him in a compromising position."

Despite receiving more rest, Rosario has made enough progress with his ankle that he was available to the Rockies to pinch-hit if needed Monday and could make the start Tuesday.

"I think there's a real good chance we'll have him available to catch tomorrow," Tracy said. "He is available to us. I just didn't want to push him into a bad spot."

Pomeranz plays catch, on track for weekend start

PHOENIX -- As expected, Rockies pitcher Drew Pomeranz, who suffered left arm soreness during his last start Friday night, will miss his next scheduled start Tuesday against the D-backs.

The 23-year-ld played catch early Monday afternoon, and the club is confident he will be back in the rotation this weekend.

"He did fine, there were no ramifications whatsoever," Rockies manager Jim Tracy said. "Moving forward there's a real good chance we'll line him somewhere over the weekend against Cincinnati if things continue to trend themselves in the way they are going."

As for who will make the spot start Tuesday for the Rockies, Tracy wasn't ready to make an announcement before Monday's game.

Pomeranz, who is 1-5 on the season with a 4.98 ERA, also reported feeling better after throwing.

"It felt good today," he said. "Felt a little better with a couple days off, we'll see how it feels tomorrow."

Chacin throws in 'pen, nearing rehab assignment

PHOENIX -- Rockies pitcher Jhoulys Chacin threw a bullpen session Monday at Chase Field, and manager Jim Tracy expects the right-hander to begin a rehab assignment in the near future.

Chacin has been on the disabled list since May 2 with inflammation in his right shoulder after beginning the season 0-3 with a 7.30 ERA.

"From my conversation, we are moving in the direction of a rehab assignment with him," Tracy said. "Because of how well he felt, we're more than likely going to push him in that direction."

Tracy, however, doesn't know when or where the rehab stint will begin.

Worth noting

• Rockies first baseman Todd Helton will not be activated Tuesday, the first day he is eligible to come off the 15-day disabled list for a right hip injury. Instead, the club will wait until it returns to Denver on Friday to activate the veteran.

"To bring him here for one or two days and to fly him here and then fly back -- we just felt that it would be in his best interest for him to remain back in Denver and rejoin us then," Tracy said.

Tracy also said Helton won't play in any more rehab games.

• Rehabbing shortstop Troy Tulowitzki, currently on the disabled list with a groin injury, appears to be nearing the point at which he will begin participating in more baseball activities.

"He's definitely moving in the right direction, he's been doing some functional stuff the last couple days," Tracy said. "When we get back on Friday, I'm sure we'll see how he is, physically. If he is progressing the way he is now, there is a possibility we'll ramp him up further and push him in the direction of some serious baseball activities. As far as any timetable in relation to his readiness, I don't have it."