Both players will have scans ahead of Sunday's La Liga opener at the Nou Camp.
Police and local councils have put restrictions in place to prevent club from selling tickets on general sale.
McGregor won the featherweight title from Jose Aldo at UFC 194.
Ibrahimovic is currently a free agent after being released by United in the summer.
The Palio di Siena has been held in the Piazza del Campo in the centre of the medieval town, twice a year, almost without fail since 1656.
Loftus-Cheek joined Palace on a season-long loan earlier this summer.
Dana White revealed Tony Ferguson would face Kevin Lee for the interim lightweight title.
Koeman has made a host of new signings but is far from finished in the transfer market this summer.
West Brom have turned down 2 bids for City for ex-Manchester United man.
Alli signed a new six-year contract at Spurs last September.
Gabriel joined Arsenal from Villarreal during the 2015 January transfer window.
Barcelona have had bids rejected for Coutinho and Dembele by Liverpool and Dortmund respectively.
Coutinho has already handed in a transfer request to leave Liverpool for Barcelona.
Liverpool and Chelsea have both been linked with Van Dijk throughout the summer.
Real Madrid defeated Barcelona 2-0 at the Bernabeu in the second leg of the Super Cup.
One officer sustained a head injury and another suffered a wrist injury, police said.
Los Blancos secure easy victory over sorry Barca at the Bernabeu.
Sigurdsson, 27, has put pen to paper on a five-year deal.
Former long-serving Reds captain and current under-18s coach believes Jurgen Klopp lacks a holding midfielder.
Ex-Reds boss unsure whether Virgil van Dijk can cure the club's defensive issues.
Barkley only recently recovered from a groin problem and a fresh issue could derail move to Tottenham.
Under-20 World Cup winner will spend the remainder of the 2017-18 campaign on loan at Craven Cottage.
Reports in Italy claim Napoli swiftly turned away an offer from Ernesto Valverde's side.
Scotland international could make a sensational return to Elland Road if Whites lose last season's top scorer.
Chairman Erick Thohir does not anticipate a deal in the final two weeks of the window.
Sigurdsson may feature against Manchester City on Monday despite not having much of a pre-season.
The 18-year-old attacker has been repeatedly linked with a move to Anfield.
Cancelo will move to the Serie A giants on a season-long loan with Geoffrey Kondogbia going the other way
Portugal international was sent off for two bookings during the 3-1 victory over Barcelona in the first leg.
Reports suggest the Red Devils boss has decided against selling fringe players to fund final summer signing.