Tierney and Lacazette have recovered from knee and hamstring injuries respectively, but they have yet to report for regular training.
Speaking before the Newcastle United match, Arteta said that the duo could be unavailable for the next few games.
“They haven’t trained with us yet. So it’s unlikely to have them ready in the next few games,” He told Sky Sports.
Meanwhile, they are trailing 2-1 after the away leg of their Europa League semi-final tie against Villarreal last week.
They must score at least once to stay in contention for the final, and Aubameyang’s availability is a big boost.
The club captain made his first start since recovering from malaria on Sunday. He is expected to lead the line in midweek.
Aubameyang bagged his 15th goal of the campaign against the Magpies.