Drogba was taken off on a stretcher after receiving lengthy treatment. He appeared to be knocked out in mid-air when challenging goalkeeper John Ruddy for a high ball and landed nastily, with the incident ensuring that 11 minutes were added at the end of a dramatic match in West London.
Drogba has since recovered after being taken to hospital and the club have since released a statement that said: ""Chelsea Football Club can confirm Didier Drogba will be released from hospital tonight following medical tests."
"The striker...is suffering from mild concussion. The club's medical staff will continue to monitor the 33-year-old over the coming days."
Jose Bosingwa put Chelsea in front with a stunning goal after six minutes, before a mistake from stand-in goalkeeper Henrique Hilario allowed Grant Holt to equalise just after the hour mark as he hooked the ball home from the edge of the box.
Ramires drew Ruddy into a foul that earned the goalkeeper a red card after 82 minutes and Frank Lampard scored from the spot, before Mata netted in the 100th minute to give Chelsea a tally of seven points from their opening three games. However, any satisfaction will have been tempered by the worrying injury suffered by Drogba.
Chelsea manager Andre Villas-Boas abandoned the 4-3-3 formation that gave him so much success at Porto in order to accommodate both Drogba and Fernando Torres in attack from the start for the first time this season, and the home side seemed to respond in an action-packed start.
Brazilian midfielder Ramires, shuttling on the right of a midfield diamond, tested Ruddy with a fine effort from 25 yards after only two minutes, while Torres almost converted from a teasing cross from Bosingwa, only to be denied by a fine block from Zak Whitbread.
After only six minutes, Chelsea were in front. Lampard played the ball square to Bosingwa and with the right-back finding himself in plenty of space 30 yards from goal, he unleashed a vicious effort that flew past Ruddy into the top-right corner of his goal.
Chelsea have made a habit of hammering weaker sides at home in recent seasons and you feared for Norwich, a side that have returned to the Premier League following back-to-back promotions under Paul Lambert. However, they refused to be overrun by their more prestigious opponents.
After 17 minutes they should really have drawn level. Wes Hoolahan, excellent in midfield for Norwich, played in Holt with an excellent pass into the box but perhaps surprised to find himself onside, the striker attempted to channel his inner Dennis Bergkamp with an elaborate spin and flick and failed to connect with the ball.
Hoolahan carved open the Chelsea defence again just before the half-hour mark as he slipped in Chris Martin, but the forward took an unnecessary touch, allowing Hilario to block. Martin took control of the loose ball and coaxed the keeper to the edge of the box before laying a pass off to Kyle Naughton, but his subsequent shot was tipped over the bar.
Holt also tested Hilario with a firm header but Chelsea regained control in a half in which they had 68 per cent of the possession and Florent Malouda, restored to the starting line-up, forced Ruddy into a smart save at his near post with an excellent volley before the half was out.
Chelsea could have doubled their lead within five minutes of the restart but Terry saw a goalbound header from a Malouda corner headed away by Anthony Pilkington. The Blues seemed in control, but a terrible mistake from goalkeeper Hilario, standing in for the injured Petr Cech, allowed Norwich back into the game.
Hilario raced off his line to try and claim a cross from Naughton but knocked into Branislav Ivanovic. The ball popped nicely into the path of Holt who showed admirable composure to hook the ball home on the volley from the edge of the box.
Chelsea wanted a quick response and Drogba went up to challenge Ruddy for a high ball, but the goalkeeper's fists accidentally connected with Drogba's face and he appeared to be knocked out cold in midair before falling to the ground and landing nastily. A lengthy stoppage was required before Drogba was taken off in a neck brace.
Villas-Boas responded by introducing Nicolas Anelka, and bringing on Mata for his debut in place of Malouda, before Norwich threatened to claim a second when Steve Morison raced onto a ball over the top. He took too long to pull the trigger though and Terry produced a brilliant recovering challenge.
After 80 minutes, a searching run from Ramires brought Chelsea a penalty when Ruddy raced off his line and brought the Brazilian down to earn a red card. Ramires was looking for contact but it was a reckless piece of goalkeeping from Ruddy, and his replacement Declan Rudd was unable to prevent Lampard from scoring from 12 yards.
Due to Drogba's injury, 11 minutes were added at the end of the second half, and Ivanovic should have made the game safe when he somehow headed wide from a Lampard cross with the goal at his mercy.