diff --git a/app/controllers/student_teams_controller.rb b/app/controllers/student_teams_controller.rb
index 4763841b180..2dc1932bbfa 100644
--- a/app/controllers/student_teams_controller.rb
+++ b/app/controllers/student_teams_controller.rb
@@ -51,11 +51,11 @@ def view
     @send_invs = Invitation.where from_id: student.user.id, assignment_id: student.assignment.id
     @received_invs = Invitation.where to_id: student.user.id, assignment_id: student.assignment.id, reply_status: 'W'
 
-    @current_due_date = DueDateHelper.current_due_date(@student.assignment.due_dates)
+    @current_due_date = @student.assignment.current_due_date
 
     # this line generates a list of users on the waiting list for the topic of a student's team,
     @users_on_waiting_list = (SignUpTopic.find(@student.team.topic).users_on_waiting_list if student_team_requirements_met?)
-    @teammate_review_allowed = DueDateHelper.teammate_review_allowed(@student)
+    @teammate_review_allowed = @student.teammate_review_allowed
   end
 
   def create
diff --git a/app/helpers/due_date_helper.rb b/app/helpers/due_date_helper.rb
deleted file mode 100644
index a6546afc729..00000000000
--- a/app/helpers/due_date_helper.rb
+++ /dev/null
@@ -1,14 +0,0 @@
-module DueDateHelper
-  def current_due_date(due_dates)
-    due_dates.detect { |due_date| due_date.due_at > Time.now }
-  end
-
-  def teammate_review_allowed(student)
-    # time when teammate review is allowed
-    due_date = current_due_date(student.assignment.due_dates)
-    student.assignment.find_current_stage == 'Finished' ||
-      due_date &&
-        (due_date.teammate_review_allowed_id == 3 ||
-        due_date.teammate_review_allowed_id == 2) # late(2) or yes(3)
-  end
-end
diff --git a/app/models/assignment.rb b/app/models/assignment.rb
index 8e90cea2449..208932df845 100644
--- a/app/models/assignment.rb
+++ b/app/models/assignment.rb
@@ -650,6 +650,10 @@ def get_following_assignment_due_dates(assignment_id, topic_id = nil)
     following_assignment_due_dates = AssignmentDueDate.where(parent_id: assignment_id)[topic_due_date_size..-1]
   end
 
+  def current_due_date
+    due_dates.detect { |due_date| due_date.due_at > Time.now }
+  end
+
   private
 
   # returns true if assignment has staggered deadline and topic_id is nil
diff --git a/app/models/participant.rb b/app/models/participant.rb
index 54df02d2e44..f64abe6e398 100644
--- a/app/models/participant.rb
+++ b/app/models/participant.rb
@@ -118,6 +118,15 @@ def authorization
     authorization
   end
 
+  def teammate_review_allowed
+    # time when teammate review is allowed
+    due_date = assignment.current_due_date
+    assignment.find_current_stage == 'Finished' ||
+      due_date &&
+        (due_date.teammate_review_allowed_id == 3 ||
+        due_date.teammate_review_allowed_id == 2) # late(2) or yes(3)
+  end
+
   # Sort a set of participants based on their user names.
   # Please make sure there is no duplicated participant in this input array.
   # There should be a more beautiful way to handle this, though.  -Yang