Arsenal could join north London rivals Tottenham Hotspur in the hunt for Ajax defender Joel Veltman, [football] direct news understands.The Gunners are keen to strengthen defensively this summer as they face the prospect of losing Belgian centre-back Thomas Vermaelen, who has become unsettled at the Emirates Stadium.Although first-choice central defensive pairing Per Mertesacker and Laurent Koscielny have been in fine form this season, Arsene Wenger is keen to have another option to rotate in that position for next year, with Veltman now looking like being the Frenchman’s top target.The 22-year-old has shown plenty of promise with his displays this season, helping Ajax to a fourth straight Eredivisie title in a row with his commanding and intelligent displays at the back.Veltman also looks likely to be on show at this summer’s World Cup for Netherlands, having won his first senior cap last year under national team manager Louis van Gaal, who is reportedly keen on signing him for his next club.Word is that Arsene is quite keen on Veltman at Ajax, an Arsenal insider revealed. “If Vermaelen goes, we’ll need another option there. The problem is, van Gaal is a fan of his and might try signing him, depending on where he goes this summer.”Read more Arsenal transfer news.