Sidwell is now 35 and out of a club following his departure from Brighton in the off season.
He did not play a single game for the club this past season due to back and ankle injuries.
Now he may be done with the game.
"It's been a tough year injury-wise," the midfielder told talkSPORT.
"If you would have asked me this time this year, I was fit and healthy and looking forward to the Premier League - roll on 12 months and I've not kicked a ball. I've been out all season and it's been tough.
"I'll be honest with you, it's a bit up in the air [future in the game].
"Could it be over? Possibly.
"I've been working hard in rehab this year. It's been constant. Sometimes you need to pull the handbrake up and have a rest, but that's not really worked either.
"I need to have a good think over the summer, do a bit of training and just be honest with myself to see if can I go in and do it again.
"I'm 35, but if you'd have asked me last year I could have played until 37 or 38 easy. I'm naturally fit and it wouldn't have been a problem.
"I'm talking it down at the moment - there's still a chance I can play."