According to Bild, via Sports Witness, Arsenal remain keen on Brandt with the 25-year-old available for a fee in the region of £17.3m.
However, any final decision on Brandt's future will rest with incoming head coach Marco Rose, who may or may not decide to keep the attacking midfielder.
Nevertheless, Leno remains keen on a reunion with Brandt at Arsenal and even exchanged text messages with the Dortmund star over a potential move.
"I read the rumors with Arsenal and wrote them a few messages right away,", Leno said in an interview with German publication Sport 1. "But I don't know what is really there.
"In any case, I would be happy if he would come. Jule is a good friend, we had a very good time in Leverkusen and privately we were often out for one or two beers.
"Maybe we can experience that again in the future.
"He's also invited to my wedding, which unfortunately couldn't take place this year. We will make up for that next year."
It remains to be seen whether or not the likes of Arteta and Edu will pull the trigger on a move for Brandt, however with talks of Stan Kroenke financing a huge summer spending spree, the Gunners fans can expect a busy window.