So the other day RDJ announced a pending big announcement. I believe that it is no accident that the announcement will come on a Friday. The same day that Marvel releases the synopsis for the upcoming episode of Agents of S.H.I.E.L.D.
Want proof? During an Reddit AMA last year RDJ said that he would be open to appearing on the show, but red tape and lawyers stuff could get in the way. And who's the friend. Back in Janruary Jeremy Renner tweeted "Tues Morn. I find myself in custume again, I just can't tell you why. and it still fits!"
I can only surmize that Tony Stark and Hawkeye are going to show up in the forth episode of the second half of the season. Most likely to get some intel on Hydra after being tiped off by Coulsons team about Strucker. This would set up Age of Ultron which to my understanding starts off with the battle between the avengers and Hydra in full swing.
What do you think?