The Trinidad & Tobago international cancelled his contract at the Sky Blues so he could take up other offers before he heads off to America to play for San Jose.
Birchall has said that the possible move to America is a massive decision for him to a Trinidad & Tobago website saying: "It's a massive decision for me to make as far as my career goes and it's one which I'll have to think very carefully about and decide in maybe two weeks.
"I'm in a far better position now than I was at Coventry because both these new offers can be beneficial for me, but I've got to take a good look along with my agent and see which is the better one.
"The fact that going to the US will mean I'm closer to Trinidad is definitely something that I will think about and fitness wise I'm not worried because I will definitely be active in England before the MLS season starts.
"But I'm heading to Brighton on Monday for a week because my old manager Micky Adams wants me there and if I do well enough in that time then there's the possibility of them putting a decent deal on the table."