Arsenal manager Mikel Arteta says it is "far from ideal" that Piero Hincapie and Martin Zubimendi were injured in a post-match training session.
Piero Hincapie (right) and Martin Zubimendi joined Arsenal last summer
A training session was held after Saturday's match at Emirates Stadium for players who either did not feature in or did not play the full 90 minutes against Leeds.
Ecuador defender Hincapie was carried off by goalkeeper Illan Meslier during the session, and Arteta later confirmed Spain midfielder Zubimendi was also hurt.
Hincapie, 24, came on after 82 minutes as Arsenal saw out victory against Leeds, while Zubimendi, 27, was an unused substitute.
"We had a training session planned after the match for everyone that didn't get enough minutes, and in two unfortunate actions we lost two players," Arteta said in a news conference before Tuesday's Champions League match against Lille.
"They'll have further scans to see where they are and we'll have that time frame for how long they are going to be out for."
Source: BBC Sport