Arsenal have added Dutch defender Jurrien Timber to their Champions League squad for the second half of the season as he nears a return from injury.

Timber joined Arsenal from Ajax for around £38m during the summer but suffered a serious ACL injury during his Premier League debut and, after undergoing surgery, was left off the European squad list for the group stage.

However, Timber is now back in the squad, with Mikel Arteta handing him the senior spot which was vacated by Lino Sousa’s winter exit to Aston Villa.

Just when Timber will be back available remains to be seen. Initial estimates of seven to nine months on the sidelines would mean a return in March at the very earliest, and his inclusion in the squad suggests that sort of time frame may prove to be accurate.

Arsenal will take on Porto in the last 16 of the Champions League, but that tie will almost certainly come too soon for Timber. The first leg is scheduled for February 21, with the return fixture on March 12.

Should Arsenal progress, they may be able to welcome Timber back for the quarter-finals, which are due to get underway on April 9 and finish eight days later.

Gunners boss Mikel Arteta has been keen to ease expectations on Timber, admitting in January that the Dutchman still has a long way to go before he can even think about a return to training.

“Unfortunately, that’s a very long-term injury,” Arteta said. “He is doing really well but he is still far from being fit to train with the team, or something to compete with the team so we don’t expect him back anytime soon.”

Timber began the season as Arsenal’s starting left-back, in part due to the absence of Oleksandr Zinchenko, but his devastating injury on the opening weekend of the season soon forced Arteta into a reshuffle.

The versatile Takehiro Tomiyasu has helped out on the left at times, as has centre-back Jakub Kiwior, but Timber’s return would offer a huge boost to Arsenal’s European hopes.