The attacking midfielder needs treatment for the ankle injury that forced him off midway through the Dons' 5-0 first-leg win.
New signing David Goodwillie is ineligible to play, while Clark Robertson is also missing as he rehabilitates from a knee injury.
Vitalijs Zils and Aurimas Kucys are suspended for the Latvians after picking up red cards in Scotland.
The winners will face Dutch side FC Groningen in the next qualifying round.
Aberdeen manager Derek McInnes said: "The pitch is slightly better condition than we thought. We're trying to think what their approach to it is.
“For me, they'll come and throw caution to the wind and have a right go at us early, we've got to be ready for that.
"It is a very good lead but we know there's still work to be done in this tie. Games can turn very quickly through lack of discipline or lack of approach to it.
"We don't need to be brilliant but we do need to be professional and we do need to be wary that we have to bring individual performances to the game.
"Watching the game back [first leg] I don't think they were overly physical, I just think there was a frustration and they lost their way a wee bit and that came out in some poor discipline from their players towards the end.
"For our part we just have to make sure we're fully focused and don't get involved in anything."