WWE hopes to have The Rock back for Wrestlemania 31 in Santa Clara, CA next year and have already penciled in a potential match for him against Brock Lesnar. There are a lot of things that can happen between now and then but this is a bout the company wanted to do this year before it was learned Rock would not be available.
Another match possibility for Rock outside of Wrestlemania is one against Sting. We're told both Rock and Sting want the match, however, it's unknown when it could possibly take place. This is in addition to the aforementioned plans for Wrestlemania 31.
Sting won't be wrestling much when he starts with WWE but currently wants his run to conclude at Wrestlemania 31 next year. Therefore a bout against Rock would have to take place in the next 11 months. He is under WWE contract but we do not know when he is scheduled to officially debut.