MIAMI -- After missing almost all of last season due to injury, Marlins right fielder Garrett Cooper once again is on the 10-day injured list.

This time Cooper is expected to miss at least a few weeks with a left calf strain, incurred on Friday night and aggravated in a pinch-hit appearance in Saturday¡¯s 7-3 victory over the Rockies at Marlins Park.

Replacing Cooper on the rosters is Peter O¡¯Brien, who was recalled from Triple-A New Orleans and started in right field on Sunday in the series finale.

¡°It¡¯s definitely frustrating,¡± Cooper said on Sunday morning. ¡°After a long year of rehab, to come back and get hurt again. It¡¯s not what I want. I¡¯ll take the rehab, day-by-day.¡±

A year ago, Cooper was limited to just 14 games due to a right wrist injury that required surgery.

The Marlins had been hopeful Cooper was dealing with just a cramp and would be back in the lineup on Sunday. That changed after the 28-year-old pinch-hit in the sixth inning when he popped out and felt some discomfort in his calf coming out of the box.

¡°After the pinch-hit, I tried to run on it, and it felt like something pulled,¡± Cooper said. ¡°So, it will be a few weeks before I can start to get back to baseball stuff.¡±

Cooper won a spot on the Opening Day roster over O¡¯Brien in what the organization called its toughest roster decision.

O¡¯Brien turned heads in the organization as a September callup in 2018, batting .273 with four home runs and 10 RBIs in the final month.

In Spring Training, Cooper, despite missing substantial time a year ago, showed he was healthy, and he made the club after hitting .395 in Grapefruit League play. He is 0-for-7 on the season.

O¡¯Brien, meanwhile, hit .220/.353/.390 with one home run, four doubles and 11 RBIs in the spring. But in March, the power-hitting 28-year-old picked things up, hitting .300/.450/.533 with one home run, 11 RBIs. What set him back was he was 0-for-11 in February.

¡°That was probably our tightest one, with Pete,¡± manager Don Mattingly said. ¡°As we talked about it to our guys in Spring Training, guys fight to make the Opening Day roster. One of the things we talked about was, ¡®If you get sent down, make sure you have a good attitude, and go to work. You never know what¡¯s going to happen. It could be 10 days and you¡¯re back.'¡±

O¡¯Brien, actually, never left the Marlins¡¯ Spring Training complex in Jupiter, Fla. That¡¯s because the Triple-A season doesn¡¯t start until Thursday, and the club has still been training in South Florida.

So O¡¯Brien was able to travel to Miami in time to be in right field Sunday.

¡°It¡¯s not the first time I¡¯ve been through that in my career,¡± O¡¯Brien said. ¡°As you know, baseball is a game of ups and downs. You¡¯ve got to stay ready. You¡¯ve got to stay available. You¡¯ve got to be ready to go.¡±