DENVER -- The Rockies placed starting pitcher Juan Nicasio on the 15-day disabled list Sunday and called up reliever Guillermo Moscoso from Triple-A Colorado Springs.

Nicasio (2-3) left Saturday's game against the Dodgers in the second inning after landing awkwardly while trying to avoid a hard-hit grounder back up the mound. The Rockies diagnosed him with a left knee strain.

"We really don't think that it's anything serious, but he will have a precautionary MRI [Monday]," said manager Jim Tracy. "He's a little sore today and we're going to err on the side of caution.

Moscoso made the drive to Denver this morning after the Rockies called him last night to inform him he was being called up.

The right-hander struggled in his two starts this year after being called up April 28. He gave up six earned runs to the Mets in five innings and six more to the Braves in 4 1/3. Moscoso was optioned back to the Minors after his no-decision against the Braves on May 4.

"When the Rockies sent me down, they told me they wanted me to be aggressive and throw lots of strikes, so that's what I did," Moscoso said. "I've been attacking the zone and putting the batters away on the first three pitches, trying to keep the pitch count low and go deep into games."

Moscoso started nine games for Colorado Springs this year. He allowed over one hit per inning (60 in 50 1/3 innings) but put together a 4.66 strikeout-to-walk ratio.

Nicasio will miss his next two scheduled starts. The Rockies have two off-days scheduled in that time frame, so a four-man starting rotation of Jeremy Guthrie, Christian Friedrich, Alex White and Josh Outman could possibly work out.

Moscosco is a candidate to play piggy-back to Josh Outman -- in the process of stretching his arm out -- in Outman's next start. Outman pitched 3 1/3 innings against the Dodgers on Friday with a predetermined pitch count of 50-55 and was replaced by Carlos Torres, who gave up two runs in two innings and was promptly sent back to Colorado Springs. "We've got a lot of possibilities in play," Tracy said. "We'll find out what kind of progress [Moscoso] has made."

Fluid in elbow halts De La Rosa's rehab

DENVER -- Jorge De La Rosa was in the Rockies' clubhouse Sunday morning after his 30-day rehab assignment was called off due to a development of fluid in his left elbow.

The left-hander has missed all 52 of the Rockies' games this year after undergoing Tommy John surgery in May 2011. In six Minor League starts, he is 0-1 with a 4.76 ERA.

"There's a little fluid there, which happens periodically when recovering from Tommy John," said manager Jim Tracy. "He is going to have an MRI Monday. But he's playing a light game of catch today, so it's not something we think is too severe."

De La Rosa, a 16-game winner in 2009, will have to wait a minimum of seven games to begin his next rehab assignment.

Worth noting

• Shortstop Troy Tulowitzki (strained left groin) said he felt "pretty good" and was confident his stint on the 15-day disabled list -- on which he was placed May 31 -- will be enough to properly rehab his injury.

• After missing Saturday's game with a sore right quadriceps, third baseman Jordan Pacheco was back in the starting lineup Sunday against the Dodgers, hitting sixth.

• The Rockies officially released left-hander Jamie Moyer, making him free to sign with any team. The 49-year-old, who went 2-5 with a 5.70 ERA for Colorado, is the oldest pitcher to win a game. Moyer was designated for assignment Wednesday.

• Drew Pomeranz started Sunday for Triple-A Colorado Springs. Pomeranz, who allowed one run with seven strikeouts over 4 2/3 innings, was optioned on May 11 after going 0-2 in five starts with the Rockies. Manager Jim Tracy wants to see improvement in Pomeranz's mechanics, so as to avoid injury. Tracy also wants to see the left-hander display a consistent ability to pitch to both sides of the plate.