Ameobi trained with the Boro squad yesterday and is available to face Championship leaders Cardiff City this Saturday. He is cup-tied and ineligible to play against Chelsea in the FA Cup fifth round tie at the Riverside Stadium tomorrow night.
The 20-year-old has signed on loan until the end of the season and Mowbray hopes the arrival can get Middlesbrough back on track after slipping out of the play-off places.
Ameobi is capable of playing as a central striker, but at Middlesbrough he is likely to be used on the flanks to give the line-up more creativity.
Despite previously tending to play Luke Williams, Adam Reach, Emmanuel Ledesma or Scott McDonald on the left, Mowbray appears to be already moving towards asking Ameobi and Mustapha Carayol to operate in tandem down either side.
"Sammy gives us a different option and more options in a similar way to Muzzy Carayol," said Mowbray. "He's an out and out attacking wide player, who can operate on either side and will be ideal when we want to play with two wingers.
"In my mind Carayol is the only, what I would class, out and out winger we have at the club. He will hopefully give some players a lift and create competition."
Ameobi has only made three starts in domestic competition for Newcastle since his debut at Chelsea approaching two years ago. His only goal was a stunning, extra-time, long-range winner at Scunthorpe in the Capital One Cup in August 2011.
He has often been used as a substitute by Newcastle boss Alan Pardew, making 21 appearances from the bench, but has shown enough to warrant call-ups for England's Under-21s.
Now, ahead of the first loan stint of his career, Ameobi is looking forward to more game time. He Tweeted: "Great first day training with Middlesbrough, happy to be joining them on loan and hopefully pick up some much needed experience."
But Ameobi will have to wait until the weekend to make his Middlesbrough debut and is expected to be in the stands watching his new team-mates against Chelsea tomorrow.
The visit of the Blues - who lost their grip on third spot in the Premier League after Spurs' win over West Ham last night - provides an exciting break from the strains of the Championship.
"The FA Cup does matter to us, to the supporters," said the Middlesbrough boss. "They will want to see their team perform and give Chelsea a real game. It can be scary to think they have got a £50m striker, a £35m winger, John Terry at the back, an England centre-half in Gary Cahill - it's a great challenge and test for us.
"Then we have an even bigger game in many respects with Cardiff. We know how tough that will be too. They will be desperate after a defeat to get back to winning ways.
"The bigger the game, hopefully, the more the supporters will cheer every shot and pass. Let's hope we can achieve some positive results.
"I will pick my strongest team against Chelsea. We will pick a team to try to win both games. That's the plan, there will be no weakened teams."
McDonald and Carayol, who both came off the bench against Millwall at the weekend, could both do with starting against Chelsea to boost their own fitness levels after injury.
Mowbray thinks his players can give Chelsea a tough night even though Middlesbrough have lost seven of their last nine league games since the turn of the year.
He said: "We are playing Chelsea. They can beat anybody, they are the champions of Europe, you have to put it in to context. We will go and compete, play, fight and try to score a goal, get the fans going.
"Maybe some of the pressure will be lifted because it is not the league. Yet pressure is something footballers have to deal with all the time, we all have to deal with pressure. Expectations will be less against Chelsea and so if that helps the players to find an extra bit then great."
The Football Association have ordered all quarter-final matches to take place on the planned weekend, meaning the Chelsea tie must be decided in time for the winners to take on Manchester United at Old Trafford on March 10.
As Chelsea face a trip to Steaua Bucharest in the Europa League on March 7, the only available date for a replay at Stamford Bridge with Middlesbrough is Monday, March 4, which is just two days after both teams are scheduled to play league games - and a day before Boro are due to travel to Huddersfield.
* Luke Williams reminded Mowbray of his own attacking potential yesterday by scoring a hat-trick in a 3-1 win over Blackburn for Middlesbrough's Under-21s at Rockliffe Park.
After falling behind to former Newcastle striker Leon Best's opener, Williams stole the show and started by hitting a stunning equaliser five minutes later.
His second curled through a crowded area with eight minutes left before adding a third by reacting first to turn in the rebound from his own saved penalty.
Boro: Ripley; Bennett, Waters, Burgess, Reach; Jackson, Brobbel, Morris, L Williams; Kneeshaw, Jones. Subs: Sirrell, Montgomery, Fewster, Rhoden, Burn.
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