Proto Man -- Mega Man's dying brother, originally from Mega Man 3 -- will be playable in Mega Man 9 via DLC that becomes available the week of Monday Oct 6. GamesRadar is reporting the news with two tiny developmental screen shots (jump), illustrating Proto Man's slide and charge attacks -- which Mega Man is not capable of doing in this game.
It sounds like Proto Man will play close to the original guy, too:
Proto Man can deflect most bullets with this shield, but larger blasts will still cause damage and push him back twice as far as Mega Man. Being struck also interrupts his charge shot. All the Rush adaptors change to Proto adaptors as well - Proto Sled, Proto Coil etc.
GamesRadar reports that Proto will cost $1.99/200 Wii points/160 XBLA points.
Mega Man 9 -- Proto Man DLC On the Way [GamesRadar, thanks reader Kevin A.]