Arsene Wenger says the 33-year-old Czech midfielder, who scored in the 4-1 victory over Sunderland on Saturday, must stay as he continues to make a significant contribution
Goal exclusively revealed in November that the midfielder would be offered a new deal if he featured in 25 games for the club.
Rosicky made his 26th appearance in all competitions for the Gunners in the 4-1 victory over Sunderland on Saturday, with Wenger "absolutely adamant" he must keep the 33-year-old.
"Tomas Rosicky will stay," Wenger told reporters. "We have an agreement with him and it will come out soon.
"I am absolutely adamant he has to stay at the club."
Rosicky returned to the starting lineup on Saturday and scored as Mesut Ozil was rested, leaving Wenger to sing the experienced midfielder's praises.
He added: "I think when he arrived here he was less a tactical player.
"He was purely creative, offensive player. Today he is a real organiser on the pitch as well. I like to have him in the team because he gives a real structure to our team."