Brockers believes Watt's addition to the Arizona Cardinals still isn't enough to give them the edge over the Rams' defensive line led by Donald.
"You already know that question. It's all about consistency," Brockers said to TMZ Sports. "We all know who the real 9-9 is."
"Our (defensive line's) been working, been the best or one of the best," he added. "Our record's proven."
Donald and Watt have combined for six NFL Defensive Player of the Year nods. They're just two of three players in league history to win the award three times each, joining Hall of Famer Lawrence Taylor.
Watt joined the Cardinals in early March on a two-year contract. Arizona finished with 48 sacks in 2020 but narrowly missed the playoffs.
Donald is coming off a 13.5-sack campaign as part of a Rams unit that led the NFC in sacks with 53.