The episode also marks the beginning of Alyson Hannigan's maternity leave; Lily appears only in the cold open.
Marshall decides to run a fantasy baseball league, but quickly becomes overwhelmed by the additional responsibilities and his coworkers' demands.
Barney becomes incredibly jealous after hearing of this, and unable to talk it over with Lily, confesses his love of Robin to Marshall, who reveals he already knows.
PJ eventually decides to leave, perversely giving Robin a letter of explanation, and Ted a bouquet of roses.
[1] In November 2008, Cobie Smulders and her boyfriend Taran Killam (who plays the character Blauman) announced that they were expecting their first child.