West Ham manager Slaven Bilic
The former Croatia manager will also have the Europa League to contend with should they come through a qualifying play-off against Romanian champions FC Astra - who knocked the Hammers out the competition last season.
West Ham have signed Norweigan midfielder Havard Nordveit, Algerian attacker Sofiane Feghouli, former Manchester United youngster Ashley Fletcher, Besiktas winger Gokhan Tore, forward Andre Ayew and left-back Arthur Masuaku this summer. Argentinian Jonathan Calleri will also arrive on loan subject to a work permit.
Meanwhile, Bilic sent back loan players Victor Moses, Emmanuel Emenike and Alex Song to their respective clubs while homegrown Hammer James Tomkins was sold to Crystal Palace for £10 million.
AC Milan's Carlos Bacca
Bacca to the drawing board?
And while Bilic hinted he would like to make one more signing ahead of Monday's season opener at Chelsea, a triple injury boost could put paid to any more incomings.
Speaking to West Ham's official website, head of medical and sports science, Stijn Vandenbroucke, revealed there is encouraging news on the fitness of injured trio Manuel Lanzini, Aaron Cresswell and Gokhan Tore.
Lanzini injured his knee while on Olympic Games duty with Argentina and has been wearing a knee brace for a month while Cresswell was ruled out for four months after being cynically scythed down in a pre-season win over German side Karlsruher and injuring his knee.
Tore was injured in training ahead of West Ham's Europa League away tie against NK Domzale when he too suffered a knock to his knee.
West Ham's Manuel Lanzini celebrates
Trio ahead of schedule
But Vandenbroucke told whufc.com all three are ahead of schedule.
"Manuel is out of the brace and has entered a new phase in his rehab and started running on Wednesday," Vandenbroucke said.
"(Aaron) did not require an operation and is making very good progress. Aaron has been wearing a brace and using crutches for a few weeks. He has now started walking with the brace, partially weight bearing. On Sunday we will take the brace off and progress to the next steps in his rehabilitation process.
"(Gokhan) had a significant trauma to his knee and rehabbed very well with our medical team and rehab fitness coach Eamon Swift, finishing those sessions on Wednesday. He will resume training with the squad today (Thursday)."
Selection headache may convince Bilic business is done
With Lanzini and Tore back in contention in the coming weeks and Cresswell ahead of schedule, West Ham's squad suddenly looks deep and strong.
It will pose a number of selection headaches for Bilic and could persuade him he does not need any more reinforcements this summer, particularly if - as has been widely reported - Bacca is reluctant to move to England.