MIAMI -- Many of the Marlins’ prospects who are close to being big league ready are still refining their skills this month in the annual instructional league.

Each September and early October, the Marlins invite about 40 prospects to get additional instruction at their Roger Dean Chevrolet Stadium complex in Jupiter, Fla. They work with invited coaching staff and managers, and eventually play games, often with organizations that also have their Spring Training facilities close to Jupiter.

Some of the prospects who could reach the big leagues in 2020 are outfielders Monte Harrison and Jesus Sanchez, shortstop Jazz Chisholm and first baseman Lewin Diaz.

Harrison, Miami’s No. 6 prospect, was tracking towards being a September callup for the Marlins, but the 24-year-old sustained a right wrist injury in late June that required surgery.

“We’re trying to make up at-bats for Monte Harrison, who missed the first part of the season with the hamstring, and missed the last part with the wrist injury,” Marlins president of baseball operations Michael Hill said.

The Marlins also are seeking winter ball options for Harrison after instrux conclude in October.

Harrison appeared in 56 games for Triple-A New Orleans, and two more at Class A Advanced Jupiter, and he combined to hit .270/.351/.441 with nine home runs, 24 RBIs and 23 stolen bases. Improving his strikeout rate this season was a priority, and he fanned 29.5 percent of the time, while walking 10 percent.

Chisholm, 21, is Miami’s No. 4 prospect. The left-handed-hitting shortstop was acquired in July for Zac Gallen.

After the trade, Chisholm played in 23 games for Double-A Jacksonville, hitting .284/.383/.494 with three homers and 10 RBIs.

Overall, he hit .220/.321/.441 with 21 homers and 54 RBIs.

“He’s getting work in the instructional league right now, and we’re in conversations to get him into winter ball, to continue to give him as many at-bats as possible,” Hill said.

Diaz was acquired from the Twins as part of the Sergio Romo trade, and Sanchez was a centerpiece in the deal with the Rays for Trevor Richards and Nick Anderson.

Diaz, the club's No. 13 prospect, combined to belt 27 home runs with 76 RBIs in Double-A, batting .270/.321/.530.

And Sanchez, the No. 3 prospect, finished up at Triple-A New Orleans, where he missed time at the end of the season due to a hamstring strain.

“Jazz is currently working out in the instructional league, as is Lewin Diaz, as is Jesus Sanchez, who is returning from his hamstring injury at the end of the Triple-A season,” Hill said.

Not included on the instrux roster is Miami's top prospect, right-hander Sixto Sanchez, who logged 114 total innings between Class A Advanced Jupiter and Double-A Jacksonville. He threw 46 2/3 innings last year in the Phillies’ system.

Sanchez combined at Jupiter and Jacksonville for an 8-6 record with a 2.76 ERA.

Sanchez was part of a Jacksonville rotation that also had prospects Jorge Guzman and Edward Cabrera. None of the three will take part in instrux.

“They all had career innings,” Hill said. “They all had tremendous seasons, when you think about what they were able to accomplish, staying healthy, taking the ball every five days and pitching career innings. We’re very happy with what they were able to accomplish in 2019.”