Manchester United identify Jamie Vardy and Javier Hernandez as options to support Romelu Lukaku

Manchester United have inquired over the availability of Leicester City forward Jamie Vardy and West Ham United outcast Javier Hernandez as Jose Mourinho bids to add to his attack in the January transfer window.

The Portuguese coach is understood to be concerned over the lack of support for summer signing Romelu Lukaku, with Zlatan Ibrahimovic having been ineffective and injury-prone since returning from seven months on the sidelines due to a knee problem.

Alexis Sanchez is also a target for United but Manchester City remain confident of securing a deal for the Chile international either this month or at the end of the season. The Premier League champions-elect have submitted a £25m bid to Arsenal and will offer the player wages of £250,000-a-week.

The Daily Telegraph understands United will have to stump up £35m to match Leicester's valuation of Vardy, who turned down a move to Arsenal in favour of signing a new contract in the summer of 2016. The England forward has mustered 10 goals from 23 appearances this term and would be available to play for the Old Trafford club in the Champions League and the FA Cup.

Hernandez, who spent five years with the three-time European champions between 2010 and 2015, has been made surplus to requirements by new West Ham boss David Moyes and is free to leave the club this month.

The Mexico international was ditched in similarly emphatic fashion by Moyes when he took charge of United and his view of Hernandez has clearly not changed having begun just one Premier League game since the Scot replaced Slaven Bilic in November.

But the major stumbling block for Mourinho remains convincing executive vice-chairman Ed Woodward that the club should invest in signing two players who due to their age will have little resale value.

Vardy turned 31 on Thursday (11 January) while Hernandez will be 30 by the start of next season and Woodward will not be easily swayed to sanction either move having outlaid £75m in the summer to signing Lukaku from Everton.

Persuading the United hierarchy to part with more money to sign Hernandez is further complicated by the club having allowed him to leave for Bayer Leverkusen less than three years ago for £7.5m, with the asking price for the ex-Real Madrid hitman expected to be at least double that fee.