Morrison suffered a head injury in Saturday's 2-2 draw with Arsenal which required stitches and was advised by Albion's medical staff not to link up with his national squad until Monday. However, Morrison, who is desperate to be involved in Scotland's friendly against Brazil in London on Sunday, made the journey to Scotland on Saturday.
Morrison said: 'The doctor tried to stop me going but I said nothing is going to stop me having the chance to play against Brazil.
'I'm really looking forward to this game. You don't often get the chance to play Brazil and test yourself.'
Bloodied but unbowed: Morrison is treated for a head injury against Arsenal
West Brom later said in a statement: 'Some of the articles we've seen suggest James has defied club orders but that could not be further from the truth.
'James was scheduled to fly up to Scotland on Saturday night but due to the fact he was suffering from concussion, we thought it would be wise to delay his flight until Monday.
'This decision had the full backing of the Scottish FA's medical department and James has now linked up with the Scotland squad and is preparing for the Brazil friendly.
'Due to the fact we have two Scotland internationals at the club - James and Graham Dorrans - we have developed an excellent relationship with Scotland's medical department and they were more than happy with how we handled James' situation last weekend.'
Morrison has been a key player in West Brom's recent upturn in form and the former Middlesbrough man believes testing himself against the five-time World Cup winners is too big an opportunity to miss.
'It's the kind of match you dreamed about playing as a kid. Taking on Spain was a great one which will stay with me forever and I'm sure this will be the same,' he told the Daily Record.
St Johnstone youngster Davidson in Scotland squad to take on BrazilWest Brom 2 Arsenal 2: Yet another Almunia clanger as Gunners slip upScotland's Naismith ruled out of Brazil clash after CIS Cup final injuriesBrazilliant! Scotland seal friendly against Samba superstars at Arsenal
Explore more:People: James Morrison Places: London, Spain, Scotland, Brazil