Arrival of N'Golo Kante raised questions over the Serbian's future in west London.
Swede signed a one-year deal at Old Trafford this summer.
This follows May's confirmation that last-eight replays in the competition will be scrapped this season.
Former Liverpool star had been linked with a move to Juventus but will continue at the Nou Camp instead.
Gazidis says it is difficult to compete as increased financial power has allowed lower clubs to bid for top targets.
Frenchman has been strongly linked with a €120m move to Old Trafford.
Hammers are looking to sign a replacement for Aaron Cresswell.
The Spaniard moved from Barcelona to the Gunners when he was a teenager.
Dortmund will be looking to repeat their opening game win over United when they take on Guardiola's team.
Manchester United and City are also reportedly interested in the Brazilian sensation.
Blaise Matuidi played every game in France's run to the final of Euro 2016.
Joao Mario won the 2016 European Championship with Portugal in July.
Zinedine Zidane says 'anything can happen' before transfer window closes
Alexandre Lacazette has scored 23 goals last season and 31 the year before.
Zinedine Zidane has reportedly urged the 23-year-old to leave the Bernabeu this summer.
Mane has scored 11 and assisted 6 in 37 appearances for Southampton last season.
Liverpool and Chelsea face each other in the International Champions Cup on 28 July in Pasadena, California.
Ryan Kent made his Liverpool debut in the FA Cup clash against Exeter City last season.
Arsenal are currently in the US where they will play San Jose on Thursday, 28 August.
European champions begin their pre-season against Ligue 1 champions in Ohio.
Argentina international follows Gareth Bale and Cristiano Ronaldo as the third most expensive footballer ever.
Striker was expected to join Marseille on loan as part of the deal to bring Georges-Kevin Nkoudou to Spurs.
Move to England reportedly collapsing over Red Devils' refusal to pay agent fees.
The Argentinian forward will miss the tour to Australia as his exit from the Calderon looks imminent.
However, the club categorically deny local reports that such an offer has now been increased to £40m.
The Gunners have made three signings thus far in the transfer window.
Nigerian has spent previous three seasons on loan at Premier League rivals.
Australia international Brad Smith is set to depart on a permanent deal to Bournemouth.
Adnan Januzaj made his full Manchester United debut under David Moyes in 2013.
Serie A giants still have to agree terms with the 19-year-old starlet.