The boy, in his mid-teens, was struck by the bike in a busy road after walking out between two buses.
Officers from the Met Police and paramedics from the London Ambulance service were called to Bexleyheath at 3.35pm.
The young boy suffered minor injuries and was taken to a south London hospital.
The incident comes after a specialist mine rescue team were forced to save a group of teenagers who got lost in a cave - while looking for Pokemon.
The four teens headed into the underground network of tunnels to play the mobile phone game that has recently taken the world by storm.
But the kids lost their way in the caves below Hawthorn in Wiltshire and were forced to wander around until they found enough mobile phone signal to call 999.
The tunnels are understood to be part of an abandoned potential emergency relocation site for the British government in the event of nuclear attack.
Dorset & Wiltshire Fire and Rescue Service warned people to stay out of the tunnels unless they have a proper map and guide.
A spokesperson said yesterday: 'The crews were able to assist key holder with leading four teenagers to safety.
'They had apparently been in the caves looking for Pokemon.
The tunnels are open to the public, but some of the areas are locked off because some of them go close to areas used by the MoD.
'The call [for help] came from the children themselves. They had got lost.
'I'm not 100 per cent sure how, but they got to a point where they had some mobile signal to call us to come and find them.
They were given the information I have just given - do not to go into the caves unless you know what you are doing, you've got a map and you've got an experienced guide with you.'
The teenagers were lost in the Boxfields Caves, under Hawthorn, near Corsham, Wiltshire, are near MoD Corsham and reach depths of up to 120ft.
The kids called for help at around 5pm on Thursday, and were helped by crews from Chippenham, Corsham and Trowbridge.
Ahead of the game's European release, the NSPCC had criticised it for putting young people in dangerous situations, demanding the creators made changes to increase safety measures for its players.
It comes as British Pokemon Go users went into meltdown after having problems logging into the reality mobile game due to high demand.
It is believed that the augmented reality game's servers have been unable to cope with the amount of people attempting to access the app since it was released in the UK on Thursday morning.
Attempts to log-in to the app prompted a message for some players from developer Niantic Labs saying: 'Our servers are experiencing issues. Please come back later.'
There have been several reports by players of the game crashing or freezing over the past week since its release in the US and Australia, with users blaming Brits for hogging local servers outside of the UK in attempt to get hold of the game ahead of its official European release date.
Over half a million new players joined Pokemon Go on the EE network yesterday as the app launched in the UK, with six new Pokemon trainers created every second.
Britons became so desperate to play the game that many were using unofficial ways to get hold of it before the European release.
The game runs on your smartphone and notifies you when you are close to a nearby Pokemon, allowing you to scan your surroundings before trying to catch it using 'Poke Balls'.
The phenomenal appeal of the game and its financial potential has sent shares in Nintendo soaring by 70 per cent, boosting its market value by almost £7billion to £19.6billion.
Among the landmarks that have been designated 'Pokemon Gyms' - where players can battle against each other - are Big Ben, the London Eye and Tower Bridge.
The augmented reality game has had its critics, however, with police warning about the app being used by criminals to lure players to specific areas.
The launch of the Pokemon Go app in the UK has been criticised by the NSPCC over fears that it puts young people in 'dangerous situations'.
The children's charity said in a statement: 'It's deeply troubling that the app's owners have ignored many warning signals and well documented child safety concerns.
'It would have been better if they had taken time to reflect on these and put their young users first. Pokemon Go is setting a precedent as the most successful reality game app on the market. It's very disappointing that child safety isn't at its heart.'
Comment: Recently teenagers in Florida were mistaken for thieves and shot at. Even 'adults' are so distracted by the game they are crashing into trees, and falling from cliffs.
The statement comes after the group urged the game's developers on Wednesday to reassess the safety features of the game.
Pokemon Go is modern take on the 1990s kids' card game hit and uses your phone's GPS and clock to detect where and when you are in the game and make digital monsters 'appear' around you.
As you move around, different types of Pokémon will appear depending on where you are and what time it is - combining the game and the real world in what is known as 'augmented reality'.
Just one day after its July 6 release, Pokémon Go had already over taken Tinder in popularity and yesterday overtook Twitter in number of active users.
The Pokémon Go craze has resulted in crowds of people gathering in outside spaces as they play the game - to the alarm of many non-players who have been calling 911 to report suspicious behavior.
Within just five days of being launched an estimated 7.5 million people had downloaded the app and the numbers using it by last weekend had already exceeded those using other phone apps like Tinder.
Around three per cent of Americans with smartphones opened the Pokémon Go app by Friday, just short of the 3.5 per cent who used Twitter, according to analysts SimilarWeb.
Those numbers are now thought to have soared this week.
As the craze continued to sweep the nation, Lancashire Police issued a warning on its Facebook page to youngsters playing on Pokemon Go
Police said that youngsters could be injured looking for the Pokemon outside their homes while distracted by their mobile phones.
PC Hesketh of Lancashire Police posted on Facebook: 'We're receiving reports of wild Pokémon appearing all across Lancashire, and we've *#gottacatchemall*!
'If you're Going hunting, know someone who is, or are a proud and responsible parent or guardian of a budding Pokémon trainer; here's some tips in order to prepare for trouble and ensure everyone stays as safe as possible.'
His tips include letting family know when and where you are going; staying alert to what is going on around you; not trespassing on private land and avoiding dangerous locations.
However, some questioned the force's priorities. Bob Shepard said: 'Surely the police should be stopping and investigating crimes not talking about a game.'
But Danny Myers agreed with the warning, saying: 'Spot on Lancashire Constabulary. I had to deal with a kid today who wandered onto our industrial site trying to 'catch' one of these things totally oblivious to the dangers present!'
And Ian Dunn posted: 'There have been serious road accidents worldwide caused by this, and now it is another reason why there's a ban on mobile use while driving. Have fun though guys.'
Others were seeing the funny side. Matt Douglas quipped: 'Question: If I've just had a shower, (phone vibrates) and there's a Pokemon in my garden that I want.
'But it's rare and I don't have time to get changed so I run down and into the garden naked in public view, but still on my property, what are the odds on me being nicked..?'