The team currently sit three points clear at the top of 2.Bundesliga with three games remaining.
According to Sport, in Hagi's homeland, the playmaker is a target if they return to the top-flight for the first time since 2010.
The Romanian, a £4million summer signing after a fruitful loan spell from Genk, has previously been linked with Spanish side Sevilla and Serie A outfit Lazio.
Hagi has made 43 appearances this season, scoring seven times and assisting many more.
Meanwhile, Rangers legend Ally McCoist believes the Scottish champions should demand upwards of £25million for Ryan Kent.
The winger is expected to attract plenty of interest this summer after a fine season at Ibrox.
McCoist, like Barry Ferguson, reckons Rangers need to hold on to the attacker but is wary that an “unbelievable offer” could see him depart.
"£25 to £30million right now for Ryan Kent," he told BT Sport Scottish Football Extra. “Absolutely.
"You need Ryan Kents These are the players you need to unlock defences, to get the ball, do the stepovers, show left and go right and vice versa.
"He sees a pass, he goes and commits somebody, he'll beat somebody, he goes past somebody and another man comes to him and opens the defence up.
"He is absolutely vital to Rangers."
Kent is contracted to the club until 2023. He has reached double figures for both goals and assists this season.