Manchester United midfielder Michael Carrick believes competition for places is so great at Old Trafford that manager Sir Alex Ferguson may have a problem picking his first-choice line-up.

Having invested heavily in the summer on striker Carlos Tevez, Owen Hargreaves, Nani and Anderson, the Red Devils boss almost has an embarrassment of riches - even taking into account injuries to Paul Scholes, Mikael Silvestre, Park Ji-Sung and Gary Neville.

With youngsters Gerard Pique and Danny Simpson impressing in the midweek Champions League victory over Dynamo Kiev and 20-year-old Jonny Evans waiting in the wings, United appear to have the beginnings of the next generation.

Carrick may be one of those under the most pressure - because he is vying for a midfield place with the likes of Darren Fletcher, Anderson, Hargreaves, John O'Shea and Ryan Giggs.

He returned to action in last Saturday's 2-2 draw with Arsenal after a month out with a dislocated elbow, played against Kiev and hopes to be involved for the visit of sixth-placed Blackburn on Sunday.

But he is not guaranteed a place in the starting XI.

"The squad is terrific. A few lads have been rested, and that will continue throughout the season," said the England international.

"The manager has got a lot of bodies, but I'm sure it's a happy problem for him.

"That [competition] is what this club is all about. They are all top players - and whoever plays will not let anyone down."

United have scored 22 goals in their last eight matches, putting in some devastating performances along the way.

The rout of Kiev in midweek was the fifth time in six games United had scored four goals - with only Premier League leaders Arsenal interrupting that run at the Emirates last weekend.

"I think everyone has raised their level of performance up a notch or two now, and you can see the threat we have got now going forwards as well as defending a team," said Carrick.

"We are confident we can keep the opposition out and score goals and not lose matches."

After his return to the side, Carrick was just happy to be playing again.

"It was nice to get back. It was a frustrating break, because I was starting to play well and the team was playing well. But it is a long old season, and I am looking forward to the games ahead," he added.

With United on a roll, it was no surprise to see Nemanja Vidic sign a two-year contract extension to keep him at the club until 2012.

The 26-year-old Serbia centre-back, signed on Christmas Day 2005 from Spartak Moscow in a £7million deal, was a major factor in last season's Premier League title success.

"Nemanja has made a terrific impact at the club and has forged a partnership with Rio Ferdinand," said Ferguson.

"It's great news that he wants to be part of this exciting side for years to come."

Vidic added: "Playing in this team is a great privilege. I hope I can do my bit to bring the club even more trophies in the years ahead."