Normally, penalty calls are made by the referees.  Linesmen are left to handle icing and offside violations.  They can also stop play for a number of reasons, including hand passes, pucks played with a high stick, injuries, and a handful of other situations. 

They can stop play for situations where there are too many men on the ice, when objects are thrown on the ice from the bench or penalty box, or when a player receives a stick illegally.  In those cases, the linesman will report the issue to the referee, who makes the call. 

They can also report major penalties, game misconducts, abuse of officials, and unsportsmanlike conduct penalties at the next stoppage in play.  You may recall newly-acquired Ryan Johansen picking up a penalty for unsportsmanlike conduct after getting tossed from the faceoff circle by linesman Greg Devorski. 

Philadelphia Flyers defenseman Radko Gudas also found himself on the wrong end of a linesman’s penalty call.  After a low hit appeared to injure Lucas Lessio of the Montreal Canadiens, linesman Greg Devorski blew the whistle. During the stoppage he conferred with referees Steve Kozari and Kyle Rehman, who ultimately ended Gudas’s night early with a five-minute major for clipping and a mandatory game misconduct. 

So, yes, under certain circumstances, linesmen can call penalties.  It’s the referees’ job to do so, and they handle nearly all of the calls made.  In some situations, including the more egregious violations, though, the linesmen can also make the call. 

 

Here’s the official guidelines, from the NHL rule book:

 

32.3 General Duties – The Linesmen are generally responsible for calling violations of off-side (Rule 83) and icing (Rule 81). They may stop play for a variety of other situations as noted in sections 32.4 and 33.5 below.

32.4 Reporting to Referee – The Linesman shall give to the Referees his interpretation of any incident that may have taken place during the game. 

The Linesman may stop play and report what he witnessed to the Referees when:

(i) There are too many men on the ice (Rule 74)
(ii) Articles are thrown on the ice from the players’ bench or penalty bench (Rule 75)
(iii) When team personnel interfere with a game official (Rule 39)
(iv) When a player who has lost or broken his stick receives one illegally (Rule 10)

The Linesman must report upon completion of play, any circumstances pertaining to:

(v) Major penalties (Rule 20)
(vi) Match penalties (Rule 21)
(vii) Misconduct penalties (Rule 22)
(viii) Game Misconduct penalties (Rule 23)
(ix) Abuse of Officials (Rule 39)
(x) Physical Abuse of Officials (Rule 40)
(xi) Unsportsmanlike Conduct (Rule 75)

Should a Linesman witness a foul (above) committed by an attacking player (undetected by the Referees) prior to the attacking team scoring a goal, the Linesman shall report what he witnessed to the Referees, the goal shall be disallowed and the appropriate penalty assessed.

The Linesman must stop play immediately and report to the Referees when:

(xii) When it is apparent that an injury has resulted from a high-stick that has gone undetected by the Referees and requires the assessment of a double-minor penalty. (Rule 60)

32.5 Stopping Play – The Linesman shall stop play:

(i) When premature substitution of the goalkeeper has occurred (Rule 71)
(ii) When he deems that a player has sustained a serious injury and this has gone undetected by either of the Referees (Rule 8)
(iii) For encroachment into the face-off area (Rule 76)
(iv) When the puck has been directed with a hand to a teammate in any zone other than the defending zone and this has(v) When the puck has been batted with the hand by either center in an attempt to win the face-off in any zone  (Rule 76)
(vi) When the puck is struck by a stick above the normal height of the shoulders and this has gone undetected by either of the Referees (Rule 80)
(vii) When either team ices the puck (Rule 81)
(viii) When there has been interference by/with spectators (Rule 24)
(ix) For any infraction of the rules concerning offside play at the blue line (Rule 83)
(x) When the puck is out of bounds or unplayable (Rule 85)
(xi) When a goal has been scored that has not been observed by the Referees (Rule 78)
(xii) When the puck is interfered with by an ineligible player/person (Rule 5, 74, 78, 84)
(xiii) The calling of a penalty shot under Rule 53