AT A time when Middlesbrough are looking to strengthen rather than weaken their squad, manager Gareth Southgate is having to face up to the prospect of being embroiled in a striker crisis this summer.

With Mark Viduka being courted by at least six Premiership clubs interested in taking him next month, Southgate is also having to prepare for a battle to retain the services of Ayegbeni Yakubu.

Yakubu, after scoring 35 goals in his first two years on Teesside, has grown unsettled after losing his place to South Korean Dong-Gook Lee in the final two games of the season.

And Portsmouth, the club he left for £7.5m in July 2005, still remain admirers of the Nigerian and are exploring ways of attracting the 24-year-old back to the south coast.

Pompey have been made aware of the player's interest in returning to Fratton Park, close to where much of his family still reside, and Southgate will have to make a major decision over the coming weeks.

The Boro boss knows that spending cash this summer is going to have to be done cleverly, with creating his own funds the best way of having millions to spend after already agreeing the £7m Jonathan Woodgate deal from Real Madrid.

And if Middlesbrough were to receive their top price for Yakubu - around £10m - then Southgate's arm in the transfer market will be strengthened considerably.

However, Viduka's situation means it would hardly be ideal to lose the club's two leading marksmen at the same stage.

Should both leave then Lee, who is yet to score for the club, will be the only recognised striker available. Malcolm Christie and Danny Graham have been told they can leave.

Yakubu and Viduka scored 35 goals between them this season and were one of the major reasons why the club finished mid-table.

But there is an increasingly real prospect that neither will be on Teesside come pre-season training in July, and Southgate has already revived his interest in Arsenal striker Jeremie Aliadiere.

The young Frenchman, originally lined up as a replacement for the departed Christie, remains a target and Middlesbrough are hoping to land him for a little over £1m. West Brom's Diomansy Kamara has also been mentioned.

Southgate remains hopeful Viduka will finally pledge his future to the club, but he also realises time is running out.

The former England defender has recently revealed he was looking for an answer from the Australian - who is away on international duty - after this coming weekend. With champions Manchester United - along with West Ham and Newcastle - among a number of clubs being kept informed with developments, Viduka has to weigh up greater financial rewards against loyalty to the club he has been with for the last three years.

Southgate would hope not to lose both Viduka and Yakubu during the close-season, as he would have preferred to use this summer to recruit men for other positions.

The departures of Stuart Parnaby and Abel Xavier means Middlesbrough are lacking defensive options and Southgate is scouring the continent for a new right-back.

And, surprisingly given their options in the middle, it has been suggested north of the border he is preparing an offer of between 500,000-1m for Scotland international Russell Anderson.

Centre-back Anderson, 28, has been integral to Aberdeens rise to a UEFA Cup place this season but Dons boss Jimmy Calderwood insists he knows nothing of any interest from the Riverside Stadium.

There has been talk of Middlesbrough making a 1m bid for Russell, said Calderwood. Thats all it is, talk. If I dont know about it then it isnt going to happen.

Another defender likely to be on his way out of Middlesbrough before the start of the new campaign in August is Matthew Bates.

The former FA Youth Cup winner, who spent a part of the season at Ipswich, is wanted back at Portman Road by manager Jim Magilton. And Magilton said: Matt Bates is one I really like and we have kept in contact with him. If he comes through the pre-season fit and well and it is on then we would have him back in the building.