Murray was issued a match penalty with 2:13 remaining in Tampa's 3-1 win over Montreal on Tuesday.
After the game, Murray described what happened on the play to the Canadiens' official website.
"[Kostka]'s coming through the middle and I had a guy to my right. He’s cutting in and I’m paying attention to both guys. I’m trying to finish my check at the same time I’m trying to keep an eye on the guy next to me. I’m just happy to see him get up and doing better," Murray said. "I thought I had my arm tucked in. I’m not going to comment on it because I didn’t get a chance to look at it afterwards.
"It's a quick game, and I’ve never been suspended in nine years. I don’t think I’m a dirty player."
Kostka reportedly suffered a concussion from the hit.There is no timetable on his return to action.
The phone hearing means Murray's maximum penalty is a five-game suspension. An in-person hearing would be required for the NHL to issue a suspension longer than that.