The Melbourne Heart face runaway A-League leaders the Central Coast - their second of three games in six days - but coach John van 't Schip refuses to believe this week will define their season.After recording five straight victories during the holiday period, the Heart are winless from their past three encounters with a 2-1 loss to Perth their last result.Now they must face table-toppers the Mariners on Wednesday before rounding out their hectic schedule against Brisbane on Saturday.But van 't Schip feels even losses in both matches won't dent their finals hopes."No I don't think that (this week will define our season) at all," van 't Schip said."Of course we know that if we get results it makers it a lot easier."If we don't then we know that we're back into the big pot with all the teams that are fighting for the play-offs."So the season is by far not gone."Even if we lose the next two games, which I'm not expecting, we are still in position to make the finals."Comparisons have been drawn between the Heart's next two opponents, current league leaders the Mariners and reigning premiers the Roar.But van 't Schip feels this season's Central Coast, who have stretched their unbeaten run to 13 straight matches and sit six points clear atop the ladder, will be prove a tougher test."I think they're (Mariners) different but they're very effective," he said."The way the Mariners play they have variation."They're not a team that loses easily."They're always creating chances ... so they're always in the game and that's why they're very strong."They play differently than Brisbane but their results this season are more effective."The Heart received a blow on Monday with the news injured skipper Fred (groin) could be out for up to another six weeks but van 't Schip would rather focus on those that can fill his place."I don't want to talk about Fred every time," he said."We have to just accept that it's going to take a longer time for him to come back."All good players are difficult to replace but other players are stepping in."I'm confident in the other players and even with Fred we were going to have a tough week."Van 't Schip revealed he will stick with largely the same line-up as in the Perth match but will make a last-minute call on the fitness of Olyroo Eli Babalj (soreness).They will also be without injured defender Simon Colosimo and midfielder Wayne Srhoj.The Mariners meanwhile, will be boosted by the return of Pedj Bojic from suspension and Rostyn Griffiths from injury.The Central Coast also confirmed on Tuesday left back Joshua Rose had agreed to extend his contract with the club until 2015.Rose has become a mainstay of the Mariners defence since becoming coach Graham Arnold's first signing in 2010.