The 27-year-old has just over 12 months remaining on his current deal, and talks over a new contract have stalled in recent weeks.
However, Pulis remains hopeful that a deal can be reached for the £6m signing from Middlesbrough.
"We are desperate to keep Robert at the club and hopefully we can reach an agreement with him soon. He's been an integral part of what we've done here and it's always important to look after the players," Pulis told The Mirror.
Stoke currently sit 14th in the Premier League table.