Manchester City boss Roberto Mancini knows Adam Johnson can make life difficult for his side as he returns to the Etihad Stadium this weekend.
Mancini often tipped Johnson for big things after signing him for 7 million pounds ($11.3 million) in 2010, but the winger grew frustrated at a lack of first-team opportunities and joined Sunderland in August.
The 25-year-old spoke of his frustration and of difficulties with Mancini after making the 10-million-pound ($16.2-million) move from the Premier League champions back to his native northeast.
The England international will now get the chance to show City what it lost as the Wearsiders visit Eastlands for a Saturday fixture (7:30 a.m. ET, ESPN2).
"I think Adam played well here," Mancini said. "The problem was maybe that he didn't play always. For young players like him, it is important to play every game. I am sure he will do well for Sunderland and go to another top team because he deserves this. He is a good guy and a good player. I hope he can have a good game on Saturday because I like Adam, I think he is a really good player.
"He wanted to play every game and here it was difficult, he decided to leave."
Johnson said Friday that experience has taught him that young players have little chance of breaking into the Manchester City team.
The 25-year-old England international now believes players should think about the likelihood of them being involved in manager Roberto Mancini's first team if the opportunity to join City arises.
"Now, if I was a young lad, I wouldn't go to City," Johnson told several English newspapers. "It is excellent when a club like City come for you. Hard to turn down. But you don't actually play for the champions -- you're a squad member, which is totally different. It's not that you're not good enough, it's just that the likes of Yaya Toure are going to play ahead of you, no matter what you do."
Johnson said he suspects the large size of the champions' squad, packed with internationals, means some players are bound to develop frustrations if they are not selected regularly by Mancini.
"I think it would only be a matter of time before senior players become unhappy," he said. "You can probably have too many world-class players at once -- everyone wants to play and they're not happy to be squad players. You're going to have trouble picking a team, and leaving people in the stands. I was one of them last season.
"(Mancini) wanted that many players in the squad. He's got to deal with it, hasn't he?"
City was well aware of the problems Sunderland can pose even before they signed Johnson.
Last season the Black Cats did more than any other side to derail City's title bid, beating City at the Stadium of Light and then claiming a draw at Eastlands.
They were in fact only five minutes from winning that second game as well, but two late goals saw the hosts snatch a point in a 3-3 thriller in March.
"It is very difficult because every time Sunderland play against us they play a fantastic game," Mancini said. "Last year the point we got against Sunderland after we were 3-1 down with five minutes to go, and we equalized in the end with (Aleksandar) Kolarov, was an important point in the league.
"I think we need to remember that game. It is important we get three points but it will be a tough game. We need to play well."
Mancini is not happy to be in action so early in the weekend program after featuring in the Champions League on Wednesday.
City played out a pulsating 1-1 draw with Borussia Dortmund and the Italian does not feel the time between games is sufficient.
"Now we need to recover very well because we play Saturday 12:45 -- I don't understand this," he said. "It is incredible that we play Wednesday night and now have two days and 12 hours to recover very well. We didn't play a very good game but we lost a lot of energy in the game and we need to recover.
"Everywhere (else) the team that plays in the Champions League plays three days or four days before the game and then after, three days minimum to play another game. Here, this is strange."
Mancini must lift the mood after the Dortmund encounter, which left City with just a point from their opening two games in Champions League Group D.
That is the same position City was in at the same stage last season, when it failed to qualify from its group.
The defensive performance was also a concern with City indebted to the brilliant Joe Hart for making several world-class saves to keep the Germans at bay.
City then only claimed a draw after Balotelli tucked home a controversial last-minute penalty.
"It is finished now, this game. We have two days to recover for the next game," Mancini said. "Last year Sunderland took four points against us and it is important we know this will be a tough game."
City has injury concerns over midfielders Javi Garcia and Yaya Toure, but Mancini could restore England international Joleon Lescott in central defense, having left him on the bench -- not for the first time in a key fixture this season -- on Wednesday.
"We play another game in two days and now we have four or five players fresh. Joleon is an important player for us," Mancini said.
Garcia (thigh) was substituted in the first half against Borussia Dortmund in midweek while Toure appeared to be limping towards the end of the game, although Mancini played down fears.
Information from Press Association was used in this report.