We've been asking ourselves that question for a couple of months, but it's hard not to notice that Krejci's play has diminished steadily since he started using "maintenance day" excuses for missing practice.
The timeline of Krejci's season is telling:
10/9 through 1/29
5-11-16 on PP
1/30 - Excused from practice for "maintenance day"
1/31 - present
0-0-0 on PP
Twice in the past two weeks -- the 11th and 25th of March -- Krejci was excused from practice, again with vague references to an injury but without specific explanation. On March 5th, coach Claude Julien broke up the line of Wheeler-Krejci-Ryder which had declined in productivity along with the rest of the team. Wheeler and Ryder continued to play well with other linemates, but Krecji faded to the third line. Perhaps more telling are his time-on-ice numbers, which have dropped sharply.
Of course the Bruins are unlikely to reveal anything, as they get KGB-level tight-lipped as April approaches. But there is clearly something wrong with Krejci's game, and it's obviously tied to the past couple of months (specifically, since he scored an OT game-winner against the Caps on 1/27). If he doesn't find his game soon, it's hard to imagine the Bruins will play the kind of 4-line hockey that dominated their opponents through the midway point of the season.