AUBURN HILLS, Mich. — Celtics guard Tony Allen will miss his second straight game during Game 6 of the Eastern Conference Finals tonight with an Achilles’ tendon injury. Allen initially suffered the injury while playing in a 1-on-1 competition during Tuesday’s practice. He made the determination that he wouldn’t be playing tonight after testing it during shoot around this morning at The Palace of Auburn Hills. Forward Brian Scalabrine is expected to be activated in Allen’s place for the second straight game. Scalabrine, however, did not play in Game 5.