"Honestly, (Hader is) a guy that we get asked about a lot," Arnold, who has been with the Brewers since 2015 and just recently earned a promotion to general manager while keeping his senior vice president title, told MLB Network Radio on Sunday.
"He's been arguably, maybe the best reliever you know of the last several years in Major League Baseball," he continued. "This guy is the keystone of the back of our bullpen and an anchor, and a guy that we need frankly. I feel like he's a guy that's a big part of our future here."
Arnold's comments come after rumors earlier in the month about the team planning to listen to trade offers for Hader this winter.
"Certainly we're getting a lot of interest in him, as we should," Arnold said.
"But that being said, you know, I anticipate that he's going to be part of our bullpen here in 2021," he added. "But, obviously, we're in a situation where it's important to always keep our options open at any point if really somebody calls."
Hader, 26, qualified for arbitration one year earlier than normal as a Super Two player. The left-hander is projected to earn between $4.5-6.8 million during his second year of arbitration eligibility, according to MLB Trade Rumors. The two-time All-Star is under team control through 2023.
Over 19 innings last year, Hader posted a career-worst 3.79 ERA and 4.03 FIP while making 21 appearances and collecting an NL-leading 13 saves.