John Diggle, played by David Ramsey on Arrow, will have trust issues with his team as the season progresses. The character's current story arc has him in a position where he doesn't want to confide in his team, even though he has now taken over both as leader and as the new Green Arrow.
At the beginning of season 6, we discovered that the explosion on Lian Yu affected Diggle both physically and emotionally. Tremors in his hand kept Diggle from firing his gun in the heat of a battle. The problem quickly gained the attention of Dinah, who confronted Diggle and threatened to expose him to Oliver. Just when Diggle decided to come clean, Oliver passed on the mantle of Green Arrow to Diggle. During last week's episode, it appeared that talking to Oliver helped Diggle move past the tremors and act as the leader that Team Arrow needed. However, the end of the episode revealed a more startling truth: Diggle is taking a drug to stop the tremors.
In an interview with Variety, David Ramsey talked about his character's struggles and says that Diggle's problem isn't a story on substance abuse, but a story about "seeing a different Diggle – whose morality is in such peril that he places this drug above his better judgment." Ramsey also shared his thoughts on Diggle's decision to keep his problem a secret from his team:
By the end of the last episode he did learn to trust his instinct, he did learn that Oliver never knew the right way – he was just trusting his instinct and hoping he won more than he lost – and that was the lesson. Diggle got that, but the larger lesson of trusting your team – and trusting your team to a point of bearing your soul and being honest – that was lost on him. He doesn’t trust his team. He doesn’t trust them enough to tell them what’s going on. It will get to the point where it becomes a life and death thing.
Diggle's use of drugs becomes compounded by the fact that he's not just a member of Team Arrow, he is the Green Arrow. Many fans, as well as Ramsey himself, believed that Diggle as Green Arrow would simply be a multi-episode arc about Oliver stepping down, but Ramsey says that the story is about John's morality. Fans will see Diggle as "a man whose values are compromised."
Fans will have to wait and see what it will take for Diggle to come back from this, and how the team will handle their leader's drug use and lack of trust. The revelation could be what leads Oliver to reclaim the mantle of the Green Arrow.
Season 6 of Arrow continues with "Reversal" tonight on The CW.