West Ham defender Dan Potts is to have more medical scans and tests, after a head injury in the midweek Premier League game against Arsenal.

Andre Marriner and Bacary Sagna Check on Dan Potts

The Gunners were 5-1 up at the Emirates, when Potts was knocked unconscious after a collision with Bacary Sagna. He needed immediate and prolonged medical attention. The 18-year-old was stretchered off the field and taken to hospital in an ambulance.

The Hammers' statement reads:

"West Ham United can confirm that Dan Potts will undergo scans and further assessment in hospital on Thursday. Potts has received hundreds of messages of support from fans via social networking website twitter. The Club would like to thank supporters for those messages and join them in wishing the No 33 well."

The youngster has made six appearances, across all competitions, for Sam Allardyce's club this season. He has also turned out for League One side Colchester, to whom he was loaned, making five appearances in the competition.

Pott's collapse was a frightening one and brought back unpleasant memories of the collapse of ex-Bolton Wanderers midfielder Fabrice Muamba, in a FA Cup tie, last year.

Big Sam on Arsenal Defeat

Meanwhile, West Ham manager Sam Allardyce has confessed surprise at the intensity of Arsenal's second half performance. The Upton Park club took the lead in the first half, through Jack Collison, but were destroyed by German international Lukas Podolski after the break; the former Bayern Munich man scored one goal and set up three others.

"I'm just stunned by what happened at the start of the second half because we were so comfortable from a defensive point of view... they got to their brilliant best and we couldn't live with them for ten minutes, and in that ten minutes they scored four goals." The ex-Bolton boss told his club's Web site.

The result keeps the Gunners in sixth, a point behind Everton and four behind north London rivals Tottenham, in the race for European football next season. The Hammers, meanwhile, extend their winless run to five matches and are drifting closer to the relegation zone.