The 22-year-old arrived on Teeside from Manchester City at the end of last month on an initial four-week deal.
However, having made three appearances for Aitor Karanka's men since then, all parties have agreed for the Argentine to remain at The Riverside until January 2.
Zuculini joined the Citizens from Racing Club in 2014, but he is yet to feature in a competitive encounter for the Premier League club.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Arsenal | 35 | 25 | 5 | 5 | 85 | 28 | 57 | 80 |
| 2 | Manchester CityMan City | 34 | 24 | 7 | 3 | 82 | 32 | 50 | 79 |
| 3 | Liverpool | 35 | 22 | 9 | 4 | 77 | 36 | 41 | 75 |
| 4 | Aston Villa | 35 | 20 | 7 | 8 | 73 | 52 | 21 | 67 |
| 5 | Tottenham HotspurSpurs | 33 | 18 | 6 | 9 | 67 | 52 | 15 | 60 |
| 6 | Manchester UnitedMan Utd | 34 | 16 | 6 | 12 | 52 | 51 | 1 | 54 |
| 7 | Newcastle UnitedNewcastle | 34 | 16 | 5 | 13 | 74 | 55 | 19 | 53 |
| 8 | West Ham UnitedWest Ham | 35 | 13 | 10 | 12 | 56 | 65 | -9 | 49 |
| 9 | Chelsea | 33 | 13 | 9 | 11 | 63 | 59 | 4 | 48 |
| 10 | Bournemouth | 35 | 13 | 9 | 13 | 52 | 60 | -8 | 48 |
| 11 | Wolverhampton WanderersWolves | 35 | 13 | 7 | 15 | 48 | 55 | -7 | 46 |
| 12 | Brighton & Hove AlbionBrighton | 34 | 11 | 11 | 12 | 52 | 57 | -5 | 44 |
| 13 | Fulham | 35 | 12 | 7 | 16 | 51 | 55 | -4 | 43 |
| 14 | Crystal Palace | 35 | 10 | 10 | 15 | 45 | 57 | -12 | 40 |
| 15 | Everton | 35 | 12 | 8 | 15 | 37 | 48 | -11 | 36 |
| 16 | Brentford | 35 | 9 | 8 | 18 | 52 | 60 | -8 | 35 |
| 17 | Nottingham ForestNott'm Forest | 35 | 7 | 9 | 19 | 42 | 62 | -20 | 26 |
| 18 | Luton TownLuton | 35 | 6 | 7 | 22 | 48 | 77 | -29 | 25 |
| 19 | Burnley | 35 | 5 | 9 | 21 | 38 | 70 | -32 | 24 |
| R | Sheffield UnitedSheff Utd | 35 | 3 | 7 | 25 | 34 | 97 | -63 | 16 |
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