The 22-year-old Teessider has battled back from three separate surgeries on his knees during his short career.
The club have confirmed that Bates has torn the anterior ligament during the club's pre-season clash at Carlisle on Saturday.
BORO PRE-SEASON FIXTURES
MACCLESFIELD 0 BORO 3 (Arca pen, Emnes, Franks)
(1st half) Coyne, Hoyte, Huth, Williams, Grounds, Yeates, Walker, Digard, Cronesberry, Aliadiere, Martin. (2nd half) Coyne, McMahon, Bates, Hines, Johnson, Smallwood, O'Neil, Arca, Porritt, Emnes, Franks.
DUMBARTON 0 BORO 5 (O'Neil, Dunlop og, Aliadiere pen, Johnson, Williams)
Jones (Coyne 46), Hoyte (McMahon 72), Bates (Wheater 72), Huth (Hines 72), Grounds (Taylor 72), O'Neil (J Johnson 72), Arca (Capt) (Williams 72), Digard (Walker 29), Yeates (A Johnson 65), Aliadiere (Franks 46), Emnes (Porritt 63).
CARLISLE 0 BORO 2 (Johnson, Williams)
Jones (Coyne 60),McMahon,Taylor (Williams 72),Bates(Walker 24),Huth,Wheater (Hines 60),O'Neil,Arca(Hoyte 60) 60),Franks,Yeates (Porritt 72),A Johnson (Martin 84)