There's no way Orlando is anything but the 4 seed and there's no way the Knicks get to the 5 seed, so Orlando's out. Chicago has a 2 and 2.5 game lead over Boston and Miami and the Knicks have a 3.5 game lead on Indy. These teams have 6-8 games left in the season so it's pretty unlikely that Chicago or NY falls, so it's probably not Chicago. That leaves Boston and Miami.
Boston has a 0.5 game lead on Miami with 8 games left and Miami has 7 games left. The 2 seed in all likelihood comes down who wins on 4/10 when they play each other. My guess is that Boston wins and it's NY-Bos in the first round. Not a great match-up, I'd much rather see Chicago or Miami since the Knicks have shown they can beat them.
EDIT:
I'm looking at Miami's and Boston's schedules and it's a bit more complicated then what I said.
Miami has 7 games against Minn, NJ, Milw, Char, Bos, Atl, and Tor. Boston has 8 games against Atl, Det, Philly, Chi, Wash twice, Mia, and they end the season at home versus NY. It's very possible that NY-Bos game could decide each team's first round opponent. If NY wins they could end up playing Miami, who they match-up better with, and Boston could play Philly. If Boston wins they would probably play NY and, probably more important to them, would have home-court advantage in a probably second round match-up against Miami. It will be an interesting two weeks.