MIAMI -- An injury that could keep Garrett Cooper on the disabled list for a while has created an opportunity for the Marlins to call up one of their top prospects.
Outfielder Magneuris Sierra, the organization's No. 6 prospect per MLB Pipeline, will be recalled from Triple-A New Orleans on Tuesday. The 22-year-old, who already is on the 40-man roster, will fill the void left after an MRI revealed Cooper has a right wrist sprain.
Sierra was one of the centerpiece players in the Marcell Ozuna trade with the Cardinals in December.
A speedster, Sierra bats and throws left-handed. In 2017, he appeared in 22 games for the Cardinals, hitting .317 with a .359 on-base percentage in 64 plate appearances.
"He's been getting better as the season's went on," Marlins manager Don Mattingly said about Sierra after Miami lost, 12-1, on Monday night. "We felt it's the right time to bring him up."

Sierra will become the second player from the Ozuna trade to join the Marlins. A few weeks ago, Miami promoted Sandy Alcantara from Triple-A, but the right-hander is currently on rehab assignment.
"It's a little bit like Sandy," Mattingly said of Sierra's promotion. "You don't feel like it's a totally finished product. It's something you're going to continue to develop, continue to teach. We feel like the time is right to give him chances out there."
Sierra got off to a slow start this season after he sustained a hamstring strain during Spring Training. In 86 games with the Baby Cakes, he produced a slash line of .260/.287/.341 with 14 stolen bases.
But Sierra has improved each month, batting .298 in July. However, he has not drawn a walk in 14 games spanning 57 at-bats.

Sierra can play all three outfield spots, and he is expected to see regular playing time -- likely in center and left field -- with Lewis Brinson on the DL. Veteran Cameron Maybin has been starting in his place. 
The Marlins also are listening to trade offers on left fielder Derek Dietrich, so Sierra could be a candidate to play more regularly if a deal is made.
Cooper jammed his right wrist in Friday's 6-5 win over the Rays at Tropicana Field, and the 27-year-old first baseman/outfielder underwent an MRI on Monday. He also was evaluated by a hand specialist.

The fact the injury is to the same wrist that landed Cooper on the DL during the first week of the season has raised the organization's level of concern.
"It's enough to know that it's the same wrist that he had injured before," Mattingly said.
Cooper, the Marlins' Opening Day right fielder, was struck on the right wrist by a pitch from Cubs right-hander Kyle Hendricks in the second game of the season. He went on the DL, and further tests revealed he had a partial tear of the right wrist tendon sheath.
While Cooper didn't need surgery, he did end up going on the 60-day DL, missing three months.

Worth noting
• Alcantara, originally scheduled to throw three innings on Monday night in a rehab assignment for Class A Advanced Jupiter, ended up going two-plus frames. He allowed five runs (four earned), walked two and struck out one, exiting after 47 pitches (26 strikes). Alcantara, Miami's No. 2 prospect per MLB Pipeline, is on the 10-day DL with a right axillary infection.
• Tayron Guerrero (left lumbar strain) is lined up to throw an inning on his rehab assignment at Double-A.