The Eredivisie's leading goalscorer Alfred Finnbogason will miss Heerenveen's play-off second leg against AZ Alkmaar on Saturday with injury.
Heerenveen face an unexpected exit from the Eredivisie's UEFA Europa League play-offs after they lost the first leg 3-0 on Wednesday, with Finnbogason injuring his knee in Alkmaar.
The Icelandic striker scored 29 goals in the Dutch top flight this season but lasted just one half at AZ in the first leg, as the hosts struck three times before half-time.
"It looks a sprain of the inner knee," Heerenveen physio Erik ten Voorde told the club's website on Thursday.
"(A scan on) Friday should show what is really going on but Alfred can't play Saturday."
Heerenveen entered the Europa League play-offs after finishing fifth in the Eredivisie's regular season - the highest of the four clubs involved - but will have to overturn a three-goal deficit at Abe Lenstra Stadion on Saturday.
AZ's performance in the first leg was a big shock as Dick Advocaat's men had failed to win in eight games in all competitions before playing Heerenveen, while the latter had won four straight matches.
After the first leg, Heerenveen head coach Marco van Basten conceded it would be difficult for his team to recover.
"We are not without a chance," the 49-year-old said.
"On Saturday, we must make it terribly difficult for AZ."
In the other play-off semi-final, Vitesse Arnhem head home after losing the first leg in Groningen 1-0.
Vitesse have not won in eight matches but held on until the 88th minute in Groningen before Lorenzo Burnet struck for the hosts.
Burnet's goal was enough for Groningen to win their seventh consecutive game and they will hope to maintain their momentum at Arnhem's GelreDome, after storming into the Europa League play-offs.
The winners of the two semi-finals will play-off for a spot in the qualifying rounds of next season's Europa League.
|5||P. van Anholt|
|34||J. van Aken|
|21||J. van den Berg|
|Coach: M. van Basten|
for D. Sinkgraven 30'
for J. van Aken 60'
for L. Slagveer 65'
|Orlando City 2 Philadelphia Union 2: Tribbett rescues point in controversial contest|
|United States 1 Ecuador 0: Last-gasp Nagbe goal lifts hosts in Copa America warm-up|
|Djourou compares Xhaka to Pirlo|
|Gallas ´very proud´ of former boss Ranieri´s title glory|
|Copa America to use goal-line technology|
|Smith likens Postecoglou to Klopp|
|Hart backs Sterling to shine at Euro 2016|
|Giovinco happy in MLS despite Euro 2016 snub|
|Balotelli set for Liverpool return, confirms Berlusconi|
|Atletico must win Champions League - Cerezo|
|Arbeloa: Mourinho didn´t get enough recognition at Madrid|
|Mijatovic: Bale can save Madrid´s season in Champions League final|
|Gallas expects Conte to revive Chelsea|
|Deschamps ´annoyed, but not worried´ by Varane´s absence|
|´Impossible´ to see MSN leaving Barcelona - Bartomeu|
|Thiago pledges future to Bayern|
|AFC Champions League Review: Urawa pay the penalty as Seoul advance|
|Uruguay v Trinidad and Tobago: Sanchez skips final to help Suarez-less La Celeste|
|Benitez ´convinced´ he can win trophies at Newcastle|
|Nigeria v Mali: Moses among many absentees for Super Eagles|
|Benitez to stay at Newcastle|
|Kramaric leaves Leicester for Hoffenheim permanently|
|Neustadter gets green light for Russia Euro 2016 selection|
|Chile v Jamaica: Copa plans crystallize in Vina del Mar|
|Ledley making progress in bid to prove Euro 2016 fitness|
|Gotze returns to Germany training|
|Ronaldo: Madrid would be smart to give me a new deal|
|Varane disappointed by Euros absence|
|Republic of Ireland v Netherlands: O´Neill wants confident display|
|Ronaldo shakes off injury in Real Madrid training|
|Atletico star Griezmann ´listening to different clubs´|
|United States - Ecuador Preview: Klinsmann pins hopes on Yedlin as Copa preparations continue|
|Gold tells Middlesbrough to ´dream on´ over Antonio|
|Schweinsteiger wants Mourinho to spice up Manchester derby|
|England v Australia: All eyes on Rashford debut|
|Aggressive Premier League better for me - Xhaka|
|Schweinsteiger ´right on schedule´ for Euro 2016|
|Darmian relishing Euros after return from injury|
|Northern Ireland v Belarus: Last chance to impress as O´Neill prepares to trim squad|
|Ventura leaves Torino amid Italy talk, Mihajlovic appointed|
|Sevilla confident of keeping Emery|
|Godin wants Atletico to use 2014 defeat as inspiration|
|Xhaka agrees Arsenal move|
|Idolisation of Ibrahimovic warranted Sweden captaincy - Hamren|
|Scholes hopes Mourinho keeps Giggs at Manchester United|
|Gotze snubbing Liverpool will boost Germany - Bierhoff|
|Bosz honoured by Ajax appointment|
|Ramos highlights Griezmann threat|
|Record-chasing Ronaldo and taming the Wolves - Real Madrid´s route to the Champions League final|
|Donnarumma dreams of being Milan captain|
|Koke: History, not revenge motivating Atletico|
|Costa Rica v Venezuela: Hosts ramp up preparations for maiden Copa America tilt|
|Argentina v Honduras: Messi and co warm up for Copa America|
|USA will win a World Cup, says Donovan|
|Pumas UNAM 2 Independiente del Valle 1 (3-3 agg, 3-5 on penalties): Hosts suffer shoot-out heartbrea|
|Gracia leaves Malaga as Rubin Kazan loom|
|Messi: Argentina deserve to be Copa America champions|
|Dybala included in Argentina´s preliminary Olympics squad|
|Mourinho and United a ´good wedding´ - Ancelotti|
|Klinsmann: Copa America better than Euros|
|Messi: Joining Barcelona not an easy decision|
|Carrico receives four-game ban for homophobic slur|
|Dani Alves wants Atletico to win Champions League|
|McNair out to impress ´world-class´ Mourinho|
|Ranieri: Premier League survival is Leicester´s priority next season|
|Argentina forward Lavezzi suffers hamstring scare|
|Koeman talks ´very positive´, say Southampton|
|Rami replaces injured Varane in France´s Euro 2016 squad|
|Matthaus applauds Gotze for rejecting ´easy solution´ of Liverpool|
|Suarez silenced his doubters - De Boer|
|AFC Champions League Review: Jeonbuk, Shanghai SIPG progress|
|Klopp can take Liverpool right to the top, says McAllister|
|Lindelof happy at Benfica amid Real Madrid, Barcelona links|
|Zidane is perfect on and off the pitch - Lippi|
|Bale: Zidane has brought the best out of Real Madrid|
|Favre takes over as Puel and Nice part ways|
|Liverpool complete Karius deal|
|Van Gaal was treated poorly by United, but Mourinho will be a success - De Boer|
|Dani Alves: I have won more titles than Pele|
|I know who I´m taking - Conte sure on Euro 2016 selection|
|Xavi backs Guardiola to ´change the face of English football´|
|Lucescu appointed Zenit boss|
|Manchester United and Liverpool hit with €40,000 fines|
|Weinzierl: I have nothing to lose at Schalke|
|Rangers complete Barton signing|
|Italy better placed as underdogs ahead of Euro´s - Motta|
|Cantona: I love Mourinho, but he is not Manchester United|
|Ben Arfa wants Lyon move - Aulas|
|David Silva praises Iniesta´s Copa del Rey heroics|
|´It was a little scare´ - Ronaldo plays down injury fears|
|Eder the real deal for Lille|
|Van Gaal treated unfairly during Manchester United spell - Daley Blind|
|Ginola doing ´very well´ after heart surgery|
|Depay rules out Manchester United exit following Van Gaal departure|
|Hojbjerg confirms desire to leave Bayern|
|Ronaldo leaves Madrid training early after knock|
|Abbiati unimpressed with Milan players´ attitude|
|Pepe calls on Madrid to continue making history|
|Ayestaran signs two-year deal with Valencia|
|Montolivo, Antonelli sign new AC Milan contracts|
|Ronaldo ready for UCL final after being rested from practice match|
|Hummels, Sanches deals will not stop Bayern spending - Rummenigge|
|Oblak´s penalty heroics, Griezmann´s Barcelona brace - Atletico Madrid´s route to the Champions Leag|
|Salvio all but confirms Gaitan will join Atletico Madrid|
|Motta warns PSG over Ronaldo, Neymar interest|
|Europa League Mourinho´s best hope for United trophy - Sheringham|
|Injustice if Iniesta never wins a Ballon d´Or - Del Bosque|
|Van Gaal didn´t deserve United sacking - Blind|
|I´ll be happy if we make Euro 2016 semi-finals - Del Bosque|
|Koke: Why would I want to leave Atletico?|
|Fofana could retire aged 25 - Lyon president|
|Sandro set to leave Barcelona|
|Silva plays down injury worries ahead of Euro 2016|
|United would be brave to appoint Mourinho, says Schmeichel|
|Neymar adamant he is happy at Barcelona|
|Wilshere: Arsenal play me out of position|
|Ryan backs former coach Neville|
|Keane talks up Galaxy move for Ronaldo|
|´Free agent´ Diarra wants Mourinho reunion|