Mackie suffered severe bruising and sharp pain when he collided with Martin Butler in a training session prior to last night's draw with Brage IF.
The centre-back will be relieved that the injury was not more serious, yet disappointed that he will likely be some way behind the rest of the squad in terms of fitness when the season gets underway in just fifteen days time.
Despite being told he is free to go if another club comes in for him, the Londoner is hoping to stay and fight for his place at the Madejski Stadium, and hopefully earn an extension to his contract which expires next summer.
Indeed, it is not in Alan Pardew's best interests to let the centre-back go. Ignoring 16-year-olds Peter Castle and Ahmet Rifat, Reading have just two other centre-backs on their books, Steve Brown and Adie Williams.
Mackie will hope to play some of Monday's friendly at Dean Court, as will Nicky Forster and Graeme Murty. Fozzy and Murts, who have also been suffering from injury, made their long-awaited come backs last night to Alan Pardew's delight.
"Those two really are massive players for us so as you can imagine it was great to see them back out there," admitted Pardew, speaking to readingfc.co.uk following last night's game.
The trio need all the practice that they can get ahead of the new season if they are to continue where they left off last year.