MIAMI -- To make room on their 40-man roster for six of their top prospects, the Marlins made a surprise move by cutting ties with left-hander Wei-Yin Chen.

Chen, who is signed for $22 million for 2020, was designated for assignment, meaning Miami now has seven days to trade or release the veteran lefty.

"This decision was not about money," Marlins president of baseball operations Michael Hill said on a conference call. "It was about building the best and deepest 40-man roster, to allow us to compete in 2020 and beyond. And that's our job, to try to manage our roster to the best of our ability."

• These top prospects got 40-man roster spots

The decision to move on from Chen left the Marlins with six openings on the 40-man roster, which were filled by right-handers Sixto Sanchez, Edward Cabrera, Nick Neidert and Humberto Mejia, along with shortstop Jazz Chisholm and first baseman Lewin Diaz.

Left off the 40-man roster was left-hander Will Stewart, who was part of the J.T. Realmuto trade with the Phillies and is now eligible for the Rule 5 Draft.

"It is a challenge, and it's a good challenge to have," Hill said. "As we've built the layers of talent throughout the system, we still believe he is a very good Major League prospect."

With Chen, the Marlins now risk being on the hook to pay all or most of the $22 million on the final year of his contract.

"We knew what was involved with Wei-Yin Chen," Hill said. "We just felt like, as we looked to 2020 and beyond, that we have to make tough decisions. But in the end, we felt like this was the best use of our 40-man roster spots, and one that put us in the best position in moving into the future."

The left-hander signed a five-year, $80 million contract with the Marlins in 2016, but he never lived up to the billing. The lefty dealt with left elbow injuries that limited him to 22 starts in 2016 and nine appearances (five starts) in '17.

Chen was moved to the bullpen in 2019, and in 45 appearances he had a 6.59 ERA in 68 1/3 innings, while making $20 million.

"I want to thank Wei-Yin Chen for his service with the Marlins," Hill said. "We now have seven days to outright trade or release him. So we will continue to see if we can find him a new home within those seven days."

In four seasons with Miami, Chen was 13-19 with a 5.10 ERA, after going 46-32 (3.72 ERA) in four years with the Orioles.

All 30 MLB clubs had until 8 p.m. ET on Wednesday to set their 40-man rosters.

According to MLB Pipeline, Sanchez is ranked as Miami's No. 1 prospect, while Chisholm is fourth, Cabrera sixth, Neidert 11th, Diaz 12th and Mejia 29th. Stewart is ranked No. 26.

Sanchez, 21, is ranked 22nd overall on MLB Pipeline's Top 100 list, and the hard-throwing right-hander is among the top pitching prospects in the game. He was acquired from the Phillies in the Realmuto trade before Spring Training started.

Chisholm, the No. 54 overall prospect, is a left-handed-hitting shortstop, acquired from the D-backs for Zac Gallen in July.

Cabrera, No. 99, is a homegrown talent, signed as a teenager from the Dominican Republic in 2015. The right-hander had a breakout 2019 season, starting off at Class A Advanced Jupiter, before being promoted to Double-A Jacksonville.

Neidert, who missed time in 2019 with a right meniscus tear that required surgery, pitched in the Arizona Fall League, and he projects to reach the big leagues at some point in 2020.

Diaz, a left-handed-hitting first baseman, was dealt to the Marlins from the Twins in July as part of the Sergio Romo trade. He is a power-hitter who hit 14 of his 27 home runs at the Double-A level after starting off at Class A Advanced.

Mejia, 22, was an international signee by the Marlins from Panama in 2013. The right-hander had a 2.03 ERA in 66 2/3 innings at Class A Clinton, before throwing 23 2/3 innings at Jupiter with a 2.28 ERA.