COMMERCE CITY — The Rapids’ midfield will be short-handed for Sunday’s MLS conference semifinal game against Sporting Kansas City.

An MRI on Friday confirmed what the Rapids feared Thursday night, that Jamie Smith suffered a torn anterior cruciate ligament in his right knee in the second half of a 1-0, wild-card playoff victory over the Columbus Crew. He is scheduled for surgery Tuesday and will be sidelined six months, which would include the beginning of next season.

The Rapids already were without captain Pablo Mastroeni, who was held out of Thursday’s game because of lingering effects from a concussion suffered Oct. 14 against Real Salt Lake. Mastroeni is likely to miss Sunday’s game as well.

The Rapids will play a two-game series with Sporting K.C., the team that finished the regular season atop the Eastern Conference.

“Having spoken to the medical staff this morning, he’s again going to be a real doubt for the Sunday game,” coach Gary Smith said of Mastroeni. “Unfortunately, he seems to be having some ongoing repercussions. I keep holding out hope that the second leg might be more realistic. It’s not a nice injury, and of course the player’s health is paramount.”

Smith has some tough decisions to make in assembling his lineup, and he may be forced to put some players in positions where they are not comfortable.

“We’re running out of bodies in there,” Smith said. “That is for sure.”