PHILADELPHIA -- Marlins infielder Neil Walker is getting a few games out of the starting lineup to rest a sore left hamstring. The 33-year-old is available to pinch-hit, but his playing time is being closely monitored.

Walker tweaked his hamstring in Thursday’s 3-1, 10-inning win against the Phillies at Citizens Bank Park. He felt some discomfort after his two-out double in the 10th inning, which set up Starlin Castro’s two-run, game-winning home run.

But on Friday, Walker didn’t start, although he walked in a pinch-hit opportunity in the Phillies’ 4-0 win. After he reached base, he was lifted for a pinch-runner.

On Saturday, Walker had a pinch-hit single in the eighth inning of the 12-9 loss to the Phillies and then was replaced by a pinch-runner.

Walker is not expected to start on Sunday, either, and with an off-day on Monday, the club will re-evaluate his situation before facing the Indians on Tuesday at Marlins Park.

“I had a hamstring injury two years ago, and it’s a little inflammation in the same spot,” Walker said.

With the Mets in 2017, Walker suffered a partial left hamstring tear in June, and with the Yankees in 2018, he had a stint on the injured list due to a left hamstring setback.

“I’ve got to make sure I take care of this,” Walker said. “We don’t think it’s anything serious. I saw the doctor [Friday].”

Walker and Martin Prado have seen a majority of the time at first base. But on Saturday, Prado was given a day off, so Miguel Rojas played first base.

“We’re going to be careful again,” manager Don Mattingly said. “Hopefully, we can get that out. He will still have a chance to swing the bat.”

Walker has appeared in 26 games and has a slash line of .250/.337/.421 with three home runs and four RBIs.

“I felt it after the double in extra innings,” Walker said. “I didn’t feel it in any single step or slide or anything like that. I’ve played a lot more this year than I had last year.”

Attacking top of zone
As the Marlins continue to rely more heavily on advanced data, they are finding success pitching in the top of the strike zone. According to Statcast, Miami pitchers are more frequently attacking the upper regions of the zone, especially compared to 2018.

Miami pitchers are getting strikes -- either swinging or called -- 28.1% of the time up in the zone. That percentage ranks 18th among MLB teams. The Rays are the most frequent collectors of high strikes, getting them on 36% of their pitches.

A year ago, the Marlins were last in getting strikes in the upper part of the zone, at 21.9%. The Red Sox were first at 31.1%.

“We're trying to expose those guys to where the highest swing and misses come from,” pitching coach Mel Stottlemyre said. “It doesn't mean we need to live there. But, you'll see a lot of our guys. They'll go down [in the zone] early. Or they'll spin some breaking balls and pitch guys backward.”

Working the upper part of the zone is one way to combat hitters who seek to elevate the ball.

It’s an organizational philosophy to pitch up and down, so hitters aren’t locked in down in the zone.

“We have guys around the system that are capable of doing it,” Stottlemyre said. “It takes a little leading, and our pitching coaches are in tune to it. It works. We track it. We stay on it. We give them the feedback. They have to have success to get guys to buy in, and believe in it, and go do it.”

Worth noting
Garrett Cooper (left calf strain) made his first rehab assignment appearance on Friday, hitting a home run for Class A Advanced Jupiter. Cooper was back in the Hammerheads' lineup on Saturday and is expected to be on Sunday. If Walker has to go on the injured list, Cooper is an option to come off.