Federal Practice Manual for Legal Aid Attorneys: 2.7.6 Remands—28 U.S.C. § 1447(c)
As the Supreme Court has observed, “normally it's the plaintiff who must seek judicial intervention if it wishes to have the matter remanded to state court.”381 28 U.S.C. § 1447(c) provides that a motion to remand on grounds other than subject matter jurisdiction must be filed within thirty days of removal.382 This implies that a motion to remand on subject matter jurisdiction grounds may be filed at any time.