Boca Juniors' pursuit of Atlanta United centerback Leandro Gonzalez Pirez was quickly stopped because manager Frank de Boer said the Argentine is too crucial to the team in its quest to defend the MLS Cup.

“We have a replacement for (Miguel) Almiron, but not for Leandro,” de Boer said on Thursday. “We don’t have that many in central defense, especially the type he is. He’s the killer.”

Almiron's sale to Newcastle in the Premier League was finalized on Thursday, ending months of speculation. The team already purchased Pity Martinez in anticipation of Almiron leaving.

However, there aren’t many left-footed centerbacks on the market, especially those who are as physical and aggressive as Gonzalez Pirez.

De Boer said the partnership Gonzalez Pirez has with Michael Parkhurst in the center of Atlanta United’s backline reminds him of the partnership he had with Jaap Stam on Holland’s national team. Stam was the enforcer; de Boer was more about precision.

“You need those qualities in the back,” de Boer said. “He’s crucial in the back. We don’t want to let him go.”

Gonzalez Pirez said earlier this week that he’s happy at Atlanta United, where he has made 64 starts the past two seasons. He finished fourth in the Defender of the Year voting last season.

De Boer said he would like for the team to add depth at centerback, particularly someone who is left-footed. Gonzalez Pirez is actually right-footed, but plays well with his left foot.

Coincidentally, the team is reportedly pursuing Florentin Pogba, who is a left-footed centerback.

“If you play with three in the back, for example, you need at least one more,” de Boer said.