“If Jadon were to leave, we would once again be active in strengthening our attack,” sports director Michael Zorc told magazine Kicker on Thursday.
“There are certainly one or two players we have our sights on.”
Sancho, 20, stood out last season with 17 league goals and as many assists as Dortmund finished second to Bayern Munich in the Bundesliga.
He scored the first hat-trick of his career in a 6-1 drubbing of bottom side Paderborn at the end of May.
The fleet-footed forward, who joined from Manchester City’s academy in 2017, has repeatedly been linked to their rivals United and Dortmund want 120 million euros for him ($136 million).
A decision whether Sancho stays or goes is expected at the end of August.
So far, Dortmund have signed Belgium international Thomas Meunier at right-back on a free transfer from Paris Saint-Germain to replace Achraf Hakimi.
The German giants are also expected to sign English youngster Jude Bellingham, 17, from Birmingham City for around 25 million euros before next term.
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