Arsenal manager Arsene Wenger said that Lukas Podolski would be out for around three weeks after the German forward injured his hamstring against Fenerbahce in the Champions League on Tuesday.
The Germany forward had to be stretchered off early in the second half of Arsenal's 2-0 win at the Emirates Stadium, which completed a 5-0 aggregate win in the play-off round tie.
Wenger also saw Aaron Ramsey, scorer of both Arsenal's goals, go off with a groin complaint, while Jack Wilshere took some heavy blows to his troublesome ankle late in the game.
He (Wilshere) looks all right. But Podolski is definitely out for 21 days and Ramsey, we have to check how severe his groin problem is tomorrow
"That's the negative of tonight. We played a heavy price on the injury front because we lost Podolski," Wenger said.
"I don't know how bad Ramsey is. I don't know how Wilshere responds to an ankle problem. We have to check that tomorrow (Wednesday) morning.
"He (Wilshere) looks all right. But Podolski is definitely out for 21 days and Ramsey, we have to check how severe his groin problem is tomorrow."
Podolski will definitely miss Sunday's north London derby against Tottenham Hotspur and faces a race to get fit in time for Arsenal's opening Champions League group-phase game on September 17 or 18.
Schalke 04, Austria Vienna and former European champions Steaua Bucharest survived drama-packed, topsy-turvy playoff ties to secure Champions League group stage places, and handsome payouts.
Schalke, held 1-1 at home by PAOK in the first leg, won 3-2 away to the Greek side in the return, scoring their second and third goals with 10 men after Jermaine Jones was sent off.
Adam Szalai scored twice for the Bundesliga side, who were facing their former coach Huub Stevens, while their other goal was a brilliant effort by Julian Draxler.
Austria Vienna, 2-0 winners at coachless Dinamo Zagreb in the first leg, took an early lead in the return, looked to have blown it as they fell 3-1 behind, only to snatch a decisive late goal which put them in the group stage for the first time.
Steaua Bucharest, held 1-1 at home by Legia Warsaw in the first leg, took advantage of a calamitous opening period from the Polish side to go 2-0 ahead inside nine minutes.
Legia fought back for a 2-2 draw on the night but it was not enough as Steaua went through on away goals following the 3-3 draw on aggregate.
Swiss team FC Basel eased through 6-2 over two legs against Bulgaria's Ludogorets.
Playoff Round 1
Arsenal (England) 2, Fenerbahce (Turkey) 0, Arsenal advanced 5-0 on aggregate
Austria Vienna (Austria) 2, Dinamo Zagreb (Croatia) 3, Austria Vienna advanced 4-3 on aggregate
FC Basel (Switzerland) 2, Ludogorets (Bulgaria) 0, FC Basel advanced 6-2 on aggregate
Legia Warsaw (Poland) 2, Ste.Bucharest (Romania) 2; 3-3 aggregate; Ste.Bucharest advanced on 2-1 away goals
PAOK (Greece) 2, FC Schalke 04 (Germany) 3, FC Schalke 04 advanced 4-3 on aggregate