HOUSTON -- Houston Dynamo forward Brian Ching, the MVP of last year's MLS Cup, is doubtful for this year's title game because of a strained left calf. Ching was hurt in the second half of the Dynamo's 2-0 victory over Kansas City in Saturday's Western Conference final. " He's working with our trainer pretty much three times a day," coach Dominic Kinnear said Tuesday. "We're going to give him every opportunity to prove his fitness to be available for Sunday. We're not going to exclude him from anything until the morning of the final." Ching scored the tying goal in overtime and made the clinching penalty kick in last year's shootout victory over the New England Revolution in MLS' championship game. This year's MLS Cup, a rematch between the Dynamo and Revolution, will be played Sunday in Washington. Ching tied for the team lead with seven goals in the regular season this year and also scored twice in the first-round playoff series win over FC Dallas. If Ching doesn't play, Kinnear is expected to move midfielder Joseph Ngwenya to forward to play next to striker Nate Jaqua.