Tomiyasu limped off in the closing stages of that match against Wolves at the Emirates Stadium, having once again get the nod over Ben White to start at right-back.
Arteta described that as a “precaution”, but Tomiyasu was ruled out of the trip to Kenilworth Road and, speaking after his side’s victory, the Arsenal boss provided a downbeat response when asked for an update on the defender.
“We had a scan and it’s not good news,” the Arsenal boss said.
“He’s got an injury in his calf and he’s going to be out for a while.”
With Jurrien Timber still a long-term absentee, having suffered an anterior cruciate ligament injury on his Premier League debut in August, it leaves Arsenal short of full-back options heading into a typically busy festive period.
White and Oleksandr Zinchenko are likely to be the preferred pairings, with Jakub Kiwior filling in at left-back if required and Cedric now the most likely alternative on the right side of defence.