Six Nations 2014: Mako Vunipola in for Italy v England in Rome

Mako Vunipola will start at loose-head prop for England in Saturday's Six Nations match against Italy in Rome.

The 23-year-old Saracens forward replaces Harlequins prop Joe Marler, 23, who is with his partner waiting for the birth of their first child.

London Wasps prop Matt Mullan, 27, comes onto the replacements bench.

Who can win the Six Nations?

Ireland have a points difference of 81 and a win of any kind against France should see them take the title, although England could catch them with a massive win against Italy. However, Ireland have only won in Paris once in 42 years.

England must beat Italy. If France then beat Ireland, the title should be England's. However, if Ireland win by as little as one point then England must win in Rome by 51 points to overhaul the current 49-point gap.

France must beat Ireland and hope England lose. But if England beat Italy by one point then the French must win by 31 points to overturn the current 29-point gap to claim the title.

If teams are level on points and points difference, then the title goes to the team who scored the most tries during the Championship.

"We have prepared for being without Joe - it is important he is with his partner at this exciting time," said England head coach Stuart Lancaster.

"Family must always come first and everyone in the squad wishes them well."

Vunipola's inclusion is the only change to the starting XV, although 22-year-old Leicester centre Manu Tuilagi also comes onto the bench in place of Saracens' Alex Goode after recovering from injury.

Italy recall captain Sergio Parisse, who returns after a thigh injury, and the number eight will equal Martin Castrogiovanni's Italian record of 105 Test caps.

Second-placed England retain a chance of winning the title on the final weekend, although Ireland lead the standings on points difference.

Lancaster's side beat champions Wales 29-18 at Twickenham on Sunday to keep the pressure on the Irish, who travel to France on Saturday.

He said: "Rome is a fantastic opportunity for us to finish the Six Nations on a high point. We want to put in a performance that backs up the previous performances. That is a big motivation for the players."

Manu Tuilagi

Blockbusting centre Tuilagi returned from a pectoral injury in Leicester's 41-18 win against Newcastle on 2 March

British and Irish Lion Tuilagi can play on the wing as well as at centre and could make his first appearance for England in a year.

He has been capped 21 times and has scored 50 international points but has played only 70 minutes for Leicester since recovering from a torn pectoral muscle that kept him out for six months.

England aim for Six Nations glory

"It is great to be back with the England boys, joining in and trying to continue the good work," said Tuilagi. "I know I have only had one game but I have been working hard and training hard.

"It has been a long time - now I'm really excited to be playing in a tough game on Saturday."

England: M Brown (Harlequins); J Nowell (Exeter), L Burrell (Northampton), B Twelvetrees (Gloucester), J May (Gloucester); O Farrell (Saracens), D Care (Harlequins); M Vunipola (Saracens), D Hartley (Northampton), D Wilson (Bath), J Launchbury (London Wasps), C Lawes (Northampton), T Wood (Northampton), C Robshaw (Harlequins, capt), B Morgan (Gloucester).

Replacements: T Youngs (Leicester), M Mullan (London Wasps), H Thomas (Sale), D Attwood (Bath), T Johnson (Exeter), L Dickson (Northampton), G Ford (Bath), M Tuilagi (Leicester).