Signs with club in 2005.
No clue what his salary was when he signed. He signed an initial pre-contract agreement to sign a professional contract on his 17th birthday on 16 March 2006.
I'm going to just guess £10k per week for 4 years. But this is guesswork. That would take him up to Summer 2010.
That would mean a £2m contract.
In summer 2009 he signed a 5 year contract worth 60k per week. £12.5m contract.
In Jan 2013 he signed 3 1/2 year contract worth £90k per week. £17m contract.
Summer 2015 he extended for another 4 years for £140k per week. £29m contract.
Okay so the initial contract ran for only 3 of the 4 years, so £10k for 3 years is £1.56m.
May 2009 until Jan 2013 he earned 60k a week. (194 weeks) so from these dates he earned £11.64m
£11.64 + £1.56m = £13.2m from his first contract in 2006 until Jan 2013. Not bad.
Anyway, 18th Jan 2013 - 31st of July 2015 he earned 90k per week. That's 132 weeks.
132 x 90k per week = £11.88m.
£11.88m + the £13.2m he had = £25.08m
Now we don't know how long he'll be on his current contract for, he may get sold, he may extended etc. But I'll work out much he's earned thus far.
31st of July until the current time = 56 weeks. 56 x 140k = £7.84m.
£7.84m + £25.08m we've already given him = £32.92m.
£32.92m Arsenal have given Theo in wages.
I'm not sure if 10k per week for the initial contract is even close to being the amount, I just guessed that much. It would be 15k it could be 20k. So there is a chance that £32.92m is wrong, but it would only be marginally, perhaps a million or two.
That's also not factoring in things such as signing on fees/agent fee/image rights/Bonuses including goals scored/appearances/assists among other things.