Oxford Silver Machine's top rider Greg Hancock is out of Wednesday's Knockout Cup second leg at Arena Essex.

Tough rival: Mark Loram

The American ace crashed heavily during Monday's 50-45 win over Ipswich in the Elite League at Sandy Lane, just one of six Oxford riders to slip up in the extremely greasy conditions.

The new air fence definitely saved Hancock from more serious injury, as his bike almost went over the top of it, and he was lucky that it didn't bounce back on top of him.

In the event, his shoulder popped out and was soon put back in.

However, he does not feel up to riding tonight and is replaced by Jason Crump.

Promoter Nigel Wagstaff said: "It couldn't happen at a worse time for us. Greg's injury is giving the club some concern and we want him fit for our busy schedule, with meetings tonight, tomorrow and Friday, and the Pairs at Swindon on Sunday."

Rafal Dobrucki also had a spill on Monday, but is expected to be fit.

Silver Machine face a tall order, with only a one-point lead to defend after winning the first leg 47-46 at Cowley.

Arena boast former Oxford rider Dean Barker and former world champion Mark Loram, plus former British champion Kelvin Tatum at reserve.