Everybody knew that Janssen was one of the best players in the Eredivisie when he was transferred from Twente. He was going to be a player who could lead the young team, and he was expected to become a regular set-play kicker in the team. In terms of these points, he has proven his high quality so far. But as many people had anticipated, it took a long time for him to be fit in the tactics of Ajax. At first many people did not believe that he was the best option as defensive midfielder. That prediction was in part proven to be right, as Janssen has recently played excellently as offensive midfielder.This was partly because of the growing injury list of the team. Striker Sigthorsson's absence forced De Boer to put De Jong at central striker, and somebody else had to replace De Jong's former position in midfield. It was a logical decision of De Boer to put Enoh or Anita at anchor, with Janssen and Eriksen playing a more offensive role. Therefore, many would think that De Boer's masterplan has been ineffective. Even an offensive team like Ajax needs at least one hardworking defensive midfielder who can provide a balance to the team. But anyway, Janssen is still one of the best players in the Eredivisie. Vitesse's Japanese defender Yasuda named Janssen when he was asked on twitter who the best player in the Eredivisie was. (He named three players; Grooningen's Tadic, PSV's Mertens and Janssen).
So I agree that Janssen should be playing as offensive midfielder in today's squad. This is because of the presence of Vertonghen. Vertonghen often decides to move into midfield to build attacks, so somebody else has to remain backwards to prepare for opponents' counter attack. Janssen simply is not suit for this role. If the club chose to buy a classical type of center back as a replacement of Vertonghen (Twente's Douglas, let's say), the situation would be different, but this is not what I want to talk about today.
Let's see Janssen's play (watch his latest video below). In the match against Heracles I felt that he was playing differently than before. Instead of concentrating on making long through passes behind the opposing defenders, he himself ran behind them and got closer to the goal.
Ajax are excellent at maintaining the ball, but they tend to fail to turn their high ball possession rate into goals. You often see the midfielders remaining where they are after passing the ball to the attackers. They rely on the attackers' individual brilliance. However, De Jong can be an exception. He is good at running behind the defense and score a goal, so when he is playing as offensive midfielder with another reliable striker up front, Ajax can put more players in front of the opponents' goal. But when De Jong has to play as striker and Eriksen and Janssen start as offensive midfielders, nobody in midfield tries to threaten the opposing goalkeeper on their own. (It is true that Eriksen has been trying to score more goals these days, but he has much room for improvement as to his shooting skills.)
This was different in the last match against Heracles. Janssen was more eager than ever to get closer to the goal. Janssen's role was more like No.10, and this was actually very effective as he scored one goal and assisted one more. I don't know if this was a result of De Boer's instruction. Also, it remains to be seen which players will be playing in midfield next match as Sigthorsson has made his comeback and De Jong no longer needs to play as striker. But as for the last match, at least, I guess everybody can agree that the man of the match was Janssen. At Twente, he scored 10 goals last season. You can say that he is not just a player who can assist others' goals, but is a great offensive midfielder who is dangerous in front of the goal.
The next match against Heerenveen will be extremely important for the title race. Keep our fingers crossed so they can remain as champions!