Koskinen is projected to be the starter, but the 31-year-old is expected to have competition from 37-yer-old Smith, who signed a one-year contract July 1.
Koskinen, who played in the NHL last season for the first time since 2010-11 following five seasons in the Kontinental Hockey League, was 25-21-6 with a 2.93 goals-against average, a .906 save percentage and four shutouts in 55 games (51 starts) for the Oilers. Smith was 23-16-2 with a 2.73 GAA, .898 save percentage and two shutouts in 42 games (40 starts) for the Flames; he played for Edmonton coach Dave Tippett for the Dallas Stars and Arizona Coyotes.
With relatively young defensemen, the Oilers will need their goalies to be a strength if they hope to qualify for the playoffs.
"I hope they both play a similar amount of games and they're both really good every one of them," Tippett said. "I thought Koskinen looked tired last season. If you watch the last 20 games, he played a lot and mentally and physically, he looked tired. [Smith] struggled the first half through some personal stuff he had, but the second half, he was a really good player, in the playoffs he was a really strong player. Obviously, I have a history with [Smith], but they're both real competitive guys."