Morrow, an Ulsterman from Dungannon, is not able to open his mouth that wide because in the build-up to the big one he suffered a fracture to his lower jaw and lost three teeth. His dentist - the Cambridge prop Christopher Hart - has rigged a temporary splint with wire and some old dentures, which will have to do until there is time to construct a proper bridge.
"I had to eat soup for a week," said Morrow, who is doing a post-graduate Certificate of Education in chemistry at Hughes Hall. "It happened against Richmond about a month ago. I ran into a guy's forehead. I wasn't concussed." But he is cussed.
Most people would not want to risk playing again, certainly not with a temporary splint. However, the 24-year-old Morrow, who plays at full- back, is made of sterner stuff. "There's a fair chance that the splint will come off in the match," he said, "but if that happens I will just hand it over to the coach and play on. It means I will have to wear a bottom gumshield as well as the usual one, but it will be worth it."
Despite looking for the record - of the 116 matches played, Oxford have 48 wins to Cambridge's 55 - it is Oxford, with their better organised pack, who are favourites. "This is the strongest side in my three years at Oxford," the coach, Steve Hill, said, "and if we play to pre-Twickenham form we should win."
Hill's opposite number, Tony Rodgers, has an extra burden to bear, besides that record. The Light Blues' hooker is his son, Stefan. Rodgers is guardedly pessimistic and fears defeat, although he said: "Oxford may be favourites, but we have some big strong guys."
Almost 65,000 supporters are expected to pack into the ground today where they will see a total of 20 non-English players (10 on each side) battling it out in one of the last of the amateur bouts in the game.
"The biggest crowd I have played in front of is 12,000 when Ulster played the Australians at Ravenhill," Morrow said. "I am trying not to get too excited. I have the Varsity match every year on television when it has always been just another match."
Not any more, though.
OXFORD v CAMBRIDGE
R Woodfine St Edmund Hall 15 R Morrow Hughes Hall
N Booth* Worcester 14 A Bidwell Hughes Hall
N Ashley University 13 M Robinson* Hughes Hall
K Shuman Templeton 12 M Denney* St Edmund's House
N Humphries St Anne's 11 S Lippiett Corpus Christi
R Governey St Edmund Hall 10 P Moran Hughes Hall
S Barry St Cross 9 G Peacocke Hughes Hall
A Collins Lincoln 1 M Foulds* Sidney Sussex, capt
P O'Connor St Edmund Hall 2 S Rodgers Homerton
A Reuben* University 3 C Hart Hughes Hall
A Roberts* New College 4 A Innes Hughes Hall
A Russell Magdalen 5 H Innes Hughes Hall
N Celliers Keble 6 O Slack S Edmund's House
D Kelaher* St Cross, capt 7 M Haslett St Catherine's
M Challender St Anne's 8 H Whitford Hughes Hall
Referee: E Morrison (Bristol) Kick-off: 2.00pm (Sky Sports 2 1.30pm)
*denotes BlueReuse content