Gardner, 32, is out of contract in the summer and this week returned from a loan spell with Preston.
The Jamaican was on the winning side in three of his four games and helped the Championship side improve their prospects of escaping relegation.
Coyle said: "The loan move gave Ricardo a month at a very good level. I have to thank Preston for allowing him to play the games he did. That was great for us.
"Now I have to be fair to Ricardo. He will return to the squad and I will give him the chance to earn that next contract."
Gardner is now expected to be included in the group to face West Ham on Saturday as are Zat Knight (knee) and Mark Davies (ankle) after injuries.
Source: PA
Source: PA