Swansea City have offered Crystal Palace an initial £7.5m for Dwight Gayle as their hunt continues for a striker. The Welsh club, four points above the relegation zone, have 22 goals from 23 Premier League matches this season.

Under the proposed deal, Palace would receive a further £500,000 for each season Swansea remain in the Premier League during Gayle’s time at the club, provided he plays a specified number of games each year. But the deal is complicated because a sell-on payment would be due to Peterborough United, from whom the player joined Palace for an initial £3.5m, then the London club’s transfer record, back in 2013.

Gayle has made only seven league appearances this season and his four goals have come in the Capital One Cup. The 25-year-old was sent off against West Ham in mid-October, setting back his hopes of a run in the team. He had recently been ruled out with a hamstring injury, but returned to play the first half of Monday’s under-21s fixture against Millwall at Tooting & Mitcham.

Palace accepted a bid worth up to £9m from Bristol City for Gayle last summer but the striker opted to stay, seeking to make his mark in the Premier League, and Norwich City also declared an interest on deadline day in September.

Their proposal, which had matched Palace’s valuation of the player, was rejected given the lack of time it would have offered Alan Pardew to identify and secure a replacement. Norwich have since signed Steven Naismith from Everton, though they remain in the market for another forward and could yet revive their interest in Gayle.

Pardew suggested on Thursday that no striker would leave Palace before the transfer window closes.

Swansea have agreed an £8m fee with Chievo for the striker Alberto Paloschi and the Premier League club are hopeful of agreeing personal terms with the 26-year-old, who is also wanted by Atalanta.