"Arrow" has been on a mid-season break since the Ghost shooting of Season 4 Episode 9 "Dark Waters". Felicity (Emily Bett Rickards) is seemingly in a coma and her fiancé Oliver (Stephen Amell) is out for revenge, meaning Team Arrow is short of the person who is capable of manning everything tech-related from their base.
Although Felicity was the only Arrow member who does not actively barge into villains' central and launch into a fist fight, she is the one person that helps everyone else with everything the team might need when they are in a fight. However, now that she is in coma, the team might need someone to help them out with that, because no one else is nearly as smart as Felicity.
Asking Cisco (Carlos Valdes) to help out would not be feasible, because they need someone hands-on and he is busy with Zoom stuff at Central City. Atom aka Ray (Brandon Routh) could also have been of great help, but it looks like he may have left Star City to figure out his life and decide if he ever wants to return or take over Palmer Technologies.
The next bet is for Team Arrow to seek the help of Felicity's employee at Palmer Tech, Curtis (Echo Kellum). As fans already know, his character is predicted to join Team Arrow as Mr Terrific, and he has already helped the team rescue Atom from Damian Darhk (Neal McDonough).
However, he is still in the dark about who the Green Arrow really is, even trying to see if Oliver is the man behind the green hood once. He does know that Felicity works with the Green Arrow, and he might cooperate with the team knowing his boss would do the same if she were not in the hospital. We assume that he could be the fill-in brains of Team Arrow, until she is fit enough to return.
We know for a fact that Felicity will return; if not in Season 4 Episode 10 "Blood Debts" which will be aired on Wednesday, 20 January, then in one of the later episodes. Curtis will most probably figure out the truth, considering he is a genius in his own right.
We also know that Curtis is a gifted athlete, having won the bronze medal for decathlon in the Beijing Olympics. May be he could use his talents to great use with Team Arrow, once Felicity makes a comeback in The CW show.