Bates missed both of City's recent back-to-back wins over Port Vale and MK Dons due to a hip problem but the defender returned to training this Thursday ahead of the visit of Stevenage to the Coral Windows Stadium.
There was some slight concern at the time over Mclean after he limped off during the MK Dons win but he has trained as normal this week. Jon McLaughlin is also fit after receiving treatment in second half of the game last weekend because of a knock.
Along with long-term injured duo James Meredith and Kyel Reid, Lewis Clarkson, Raffaele De Vita and Matt Taylor all remain sidelined though.
Parkinson said: "Batesy has trained today (Thursday).
"To be honest, he was up for playing last weekend if needed so we knew he wasn't that far off.
"He's had a good week this week now and we feel he's ready."
Speaking on McLaughlin and Mclean, Parkinson said: "Both are fine now, absolutely fine."
Opponents Stevenage will arrive at the Coral Windows Stadium this weekend currently occupying the bottom spot in the League 1 table.
Graham Westley's side have changed their formation and tactics around over the last few games in a bid to get them climbing back up the standings.
Having watched two of Stevenage's matches first hand, Parkinson knows that City will have to be on guard and ready for anything come Saturday.
Parkinson added: "I've seen Stevenage twice - I went to see them Tuesday at home to Crewe and I saw them at Rotherham when our game against Coventry was called off.
"They have changed their formation from game to game and during the game itself sometimes in recent weeks, so we have to be prepared for that.
"Because of their changes, we have to be flexible when it comes to our plans for Saturday's game.
"We have to concentrate on playing to the best of our ability and doing what we know can do well.
"As we've said all season, there is very little to choose between the teams all across this division.
"With that in mind, we know it is going to be difficult game but it is one we are very much looking forward to.
"The lads have been training great and will be ready for it come Saturday."