One of the main points of frustration for Keefe on Friday was that Holmberg took 6 minutes worth of penalties in the contest, including a double-minor for high sticking in the 1st period. The Leafs did kill off the 4-minute penalty, but were not so lucky on Holmberg's 2nd period tripping penalty, surrendering a power play goal to give the Sens a lead that they would not relinquish.
As great as Holmberg has been in the bottom six this season and as much promise as the 23-year-old has shown so far this season, it's important to remember that he is still a rookie and, at the end of the day, rookies make mistakes. Holmberg will undoubtedly learn from this and continue to get better. For now, though, it appears that he is better suited for a role in the bottom six.