Lambert has scored eleven Premier League goals for Southampton this season, while Andy Carroll's injury problems have restricted him to far fewer games and just two goals.
With attacking options such as Wayne Rooney, Daniel Sturridge, Danny Welbeck and Raheem Sterling all likely to make England manager Roy Hodgson's squad for Brazil, there are a limited number of spaces for the likes of Lambert. Southampton team-mate Jay Rodriguez, who has scored fifteen goals this campaign, looked set to be the last forward on the plane to Brazil, before picking up a knee injury against Manchester City earlier in the month that will rule him out from the England squad.
Lambert has appeared four times in an England shirt, scoring twice, while Carroll has played nine times for his country, also scoring two goals. The West Ham striker has the advantage of international tournament experience over Lambert, though, after he was selected for England's Euro 2012 campaign. Carroll scored once for Roy Hodgson's men that summer, netting in a 3-2 victory over Sweden.
Southampton's Lambert now admits that he is in a competition for places for the last England striker slot, with Carroll being his most likely opponent.
When asked if he thought the final striker's spot was between him and Carroll, Lambert acknowledged that to probably be the case.
'I think I was vying for the central position, I think Jay (Rodriguez) might have been vying for one of the wide ones. If you're asking for my opinion, that's what I think was happening'.
Both Lambert and Carroll now have four games remaining of the Premier League season to stake their claim for a World Cup spot. Southampton have a tricky run-in, with away visits to Aston Villa and Swansea, and home games against Everton and Manchester United. West Ham have, at least on paper, perhaps a slightly easier run-in, with fixtures against Crystal Palace and West Brom, before closing out the season with games against Tottenham and Manchester City.
With Hodgson selecting his initial 30-man England squad in just over a month, both Lambert and Carroll are likely to make the cut. Their form from now until the end of the season at club level, though, will surely determine who will have a place in the final 23-man party who will actually be on the plane to Brazil.