Ovechkin appeared to injure his right knee on a hit by German defenseman Marcus Kink at the Russian blue line in the second period. He reportedly stayed down for about two minutes and was unable to put any weight on his right leg as he was helped from the ice at Minsk Arena.
"We are aware that Alex Ovechkin sustained an injury during today's game vs. Germany," the Capitals said in a statement. "Our medical staff is working with Ovechkin and Team Russia to gather additional information at this time."
Vadim Shipachyov broke a scoreless tie when he scored on the power play at 3:58 of the third period. Sergei Shirokov put Russia ahead 2-0 a little more than six minutes later, and Viktor Tikhonov sealed the victory with an empty-net goal with 45 seconds remaining.
Goalie Andrei Vasilevski made 27 saves to earn the shutout for Russia (6-0, 18 points), which has clinched the top seed from Group B.
Goalie Philipp Grubauer, who is Ovechkin's teammate with the Capitals, stopped 28 of 31 shots for Germany (2-4, five points).
Russia wraps up preliminary-round play against host Belarus on Tuesday, when the Germans face off against the United States.
In other action Sunday:
United States 3, Finland 1: Forward Tyler Johnson (Tampa Bay Lightning) scored twice and forward Brock Nelson (New York Islanders) opened the scoring 19 seconds into the first period to lead the U.S. to a 3-1 win against Finland in its penultimate preliminary-round game at Minsk Arena.
With the win, the Americans clinched a spot in the quarterfinals, which begin Thursday.
The U.S. struck early when defenseman Seth Jones (Nashville Predators) fired the puck into the zone from center ice. When Finland goaltender Pekka Rinne (Predators) went behind the net to retrieve the puck, it deflected off a stanchion and to Nelson, who tipped it in from the doorstep.
"It was a crazy bounce," Nelson told the IIHF website. "We wanted to get pucks in deep right away. When I saw the puck come off the glass, I tried to get in front and get position on my guy and was able to tap it in.
"We've seen a lot of weird bounces all over the ice in this tournament. You have to stick with it and sometimes they go your way. Tonight it did."
Following a scoreless second period, Johnson's goal at 6:42 of the third gave the U.S. a 2-0 lead. Johnson advanced a pass from forward Craig Smith (Predators), and fired a wrist shot over Rinne's shoulder and into the top corner. Jones had the secondary assist to give him nine for the tournament.
"We played much better on D," Thomas said. "We did what we had to do to keep the score down and get the win. I think a better result for me goes hand in hand with that. I don't think I was any better personally than I played in the other games. If you go back and analyze those 13 goals I gave up, there might be one or two that you'd consider really bad goals."
Thomas made 22 saves for the U.S. (4-2, 11 points), which concludes its preliminary-round schedule Tuesday against Germany. Finland (3-3, eight points) returns to action Monday against Kazakhstan.
Canada 3, Sweden 2 (OT): Defenseman Ryan Ellis' (Predators) goal 2:38 into overtime lifted Canada (5-1, 15 points) past Sweden (5-1, 15 points) and into first place in Group A.
The win was also a measure of revenge for Canada. In last year's tournament, Sweden defeated Canada 3-2 in a shootout in the quarterfinals and went on to win the gold medal on home ice. The Canadians are seeking their first gold medal since 2007.
Canada scored the winner seconds after Scrivens denied Swedish forward Dick Axelsson with a left skate save. Center Mark Scheifele (Winnipeg Jets) led a 2-on-1 rush and found Ellis, who tipped it through goalie Anders Nilsson (Islanders).
"Good play by Scheifele," Ellis told the IIHF website. "The patience from Scheifele was unbelievable for such a young guy. He put it right on my tape and I just had to touch it."
Scrivens and Nilsson made 30 and 28 saves, respectively.
"I thought it was an entertaining hockey game," Canada coach Dave Tippett said. "Both teams made some mistakes that led to chances. Both goalies played very well. We capitalized on a chance in overtime and got the win."
Forward Brayden Schenn (Philadelphia Flyers) and defenseman Kevin Bieksa (Vancouver Canucks) added goals for Canada, who play Norway (2-3, seven points) Tuesday. Sweden completes its preliminary-round schedule against Italy (1-5, three points) Monday and will claim first place with a win and a Canada loss.
Czech goalie Alexander Salak made 21 saves, including on a penalty shot by Ken Andre Olimb in the second period, to earn the shutout.
Sobotka put the Czech Republic up 1-0 when he banged home a rebound after Norway goalie Steffen Soberg had made the initial stop against Tomas Hertl (San Jose Sharks). Soberg made 38 saves in the loss.
The Czechs (3-3, 10 points) can lock up third place in Group A with a win against France in their preliminary-round finale Tuesday.
Norway (2-4, seven points) still has a chance to finish fourth and advance to the quarterfinals, but it will need to beat Canada on Tuesday and get some help in other Group A action.