The 21-year-old goalkeeper has been on loan at Stockport and helped the Coca-Cola League Two side reach Monday's play-off final at the national stadium.
But he is struggling with a hernia problem that will need an operation this summer.
Ruddy played in the first-leg of the play-off semi-final at Wycombe but was left out of the return last week, a 1-0 win which took the Cheshire club through.
Stockport boss Jim Gannon said: "John has been fantastic for us ever since he has been here. He had eight clean sheets in 12 games, but as each week has gone by he has been more troubled with a hernia.
"John has got a difficult decision now with him needing an operation - I hope he delays that operation and joins us at Wembley for the final against Rochdale."