The successful coach believes that several clubs will try and lure the Dane away from the Amsterdam ArenA in the summer transfer window
The Denmark international has a contract with the Eredivisie champions until June 2014, but De Boer has little doubt that bids will come in for the 21-year-old at the end of the season.
"Clubs do not know much about football if no offers come in for Christian this summer," the Ajax coach was quoted as saying by De Telegraaf.
De Boer remained coy on whether Dortmund have already made a formal approach for Eriksen but admitted that he thinks the Dane would fit in well at the German giants.
"I wouldn't say it if [Jurgen] Klopp had given me a call about Christian, but the Bundesliga would suit him."
Sporting director Marc Overmars, meanwhile, revealed that several clubs have been in touch with Ajax over a potential move for Eriksen.
"A number of clubs have made an informal approach for Chris."
Eriksen has been a key figure at Ajax this season, netting 10 goals in 32 Eredivisie appearances.