I know it's still a little under a month away but it could be possible that the O's send three players to Kansas City this year. I don't think it is likely but it's been awhile since we were able to even have this conversation.
Adam Jones is a lock unless he completely falls off a cliff. He is actually in the running to be a starting OF (go vote if you haven't already because he can still make it in). He is the best player on the team and is the face of the franchise.
Jim Johnson looks like he has a very good chance at making the team. He is currently 2nd in saves with 19, has the 2nd lowest ERA amongst AL closers with at least 15 saves, and has a WHIP of 0.70. If he keeps it up he could have a very good shot at making the team.
After those 2 I think Jason Hammel has a slim chance to make the team as well. He is currently 11th in ERA and is 6-2. I know W/L shouldn't matter but it always does for the All Star Game. If he can string together 2 or 3 dominant outings and get his ERA under 3 and win 2 or 3 games he could have a good chance at making it if the team is still in 1st or 2nd place.
Maybe even Chris Davis can sneak in if he keeps hitting. His hopes are even slimmer than Hammel's but you never know. Amongst AL 1B he is 3rd in average, 3rd in OPS, and tied for 2nd in HR. Amongst DH he would be 3rd in HR, tied for 1st in average, 4th in OPS, and 4th in HR.
I think they will likely send Adam Jones and Jim Johnson but if Hammel or Davis goes on a tear they may be able to sneak in.