Tony Mowbray, the Boro boss, had conceded earlier in the day that there would be no further additions before the January window closed at 11pm and there were also no more departures.
Despite interest in Leroy Lita from Queens Park Rangers and offers from Turkey and Russia for Kris Boyd, who would have preferred a return to Glasgow Rangers, both players remain at the Riverside Stadium.
It means that Lita and Boyd will be in the squad to face Scunthorpe United tonight at the Riverside, when Haas is likely to be included among the subs titutes.
The 25-year-old centre-back, who has signed a one-and-ahalf year contract after moving from Bayern Munich for an undisclosed fee, had been lined up to replace David Wheater since Christmas.
Mowbray is in no doubt that his first signing will be a hit with his first task being to help lift Middlesbrough up the Championship table.
Players have come from Germany and done very well here, said Mowbray, aware that Boro have had German internationals Christian Ziege and Robert Huth in their ranks in recent years.
The boy knows he has to get in to the team and his talent will do that even if he might have to wait for his chance because of the way Seb Hines and Matthew Bates are playing.
A signing like this comes around because you have contacts in different parts of the world who understand the way you play football and look out for players who might suit the way I like to play.
I know as a manager I take care of players and like them to feel wanted. There's people out there who know the best players who I could nurture, and that's what has happened here.
Mowbray nurtured Zemmama during their time together at Hibernian. He spent five years at Easter Road showing off his Moroccan skills and Mowbray said: He's a very technical player who can handle the ball very comfortably with both feet.
Marouane had the potential to be superstar in the Middle East when I signed him from Hibernian.
He can dribble, shift the ball from side to side, be positive and create chances and he also had a great dead ball delivery.
The 27-year-old has signed a three-and-a-half year contract after Middlesbrough agreed to take over the remaining six months of a contract due to expire in the summer at Easter Road.
He has been granted a work permit but returned to Morocco last night to gain a visa and he could figure in the squad that travels to Crystal Palace on Saturday.
Mowbray who still wants Andrew Taylor to sign a contract needs as many players as he can, with 11 players ruled out through injury for tonight's visit of Scunthorpe.
Justin Hoyte, Luke Williams, Tarmo Kink, Kevin Thomson, Barry Robson, Danny Coyne, Stephen Mc- Manus, Willo Flood, Rhys Williams, Mikael Tavares are all sidelined.
The situation has left Mowbray hoping striker Scott Mc- Donald can be involved in the squad, even though the Australian was only due to return from a month's Asian Cup duty last night.
It's not ideal, said Mowbray, who has a match-day squad of 18 which includes McDonald having sold Gary O'Neil and Wheater.
But I am very conscious of not bringing it up and making a deal out of it and hopefully we can have a few more back in the next few weeks.
Despite a preference to reducing his wage bill further by offloading the likes of Boyd or McDonald, Mowbray is looking to the rest of the season.
Had further progress been made on outgoings, Boro might have stepped up interest in Sporting Lisbon's Yannick Djalo or Hamburg's Anis Ben Hatira.
Speaking hours before last night's deadline, Mowbray said: If there was to be one sale, in one specific area before the deadline, then I don't think we would be ready to go and push the button in another area.
The loan market opening in a week helps. We have some good players here and there's a togetherness when the window shuts to get the points required to push on.
Bruno Pilatos has been placed on stand by for Under- 19 England international friendly game against Germany on Tuesday, February 8 in Chesterfield.
Source: Northern Echo
Source: Northern Echo