When the Major League Soccer season started, both the New England Revolution and Chivas USA were thought to be among the contenders for the MLS Cup. The Revs have been knocking on the door for years, while Chivas had just recently joined the league's elite, having won the Western Conference regular-season crown last year.

Yet as the MLS season enters its last two months, the championship hopes for both sides have taken some hits, literally. The Revs looked the part for much of the season, but a spate of injuries spawned a slump that has seen them slide into a tie for second place in the Eastern Conference standings. Chivas meanwhile have been struggling for most of the year, and even as two straight league wins have seen them assert themselves in the race for the postseason, a season-long injury bug shows no signs of abating.

On this week's edition of "MLS Primetime Thursday," both teams will look to get well at the other's expense, and further cement their respective playoff positions.

Five story lines to follow

1. New England's Pyrrhic victory

When the Revs defeated Houston in this year's SuperLiga final, their league championship path was laid out before them. Not only had they finally beaten their nemesis from the last two MLS Cup finals, but they did so with a shorthanded squad. Yet that may end up being the high point of their season, as a second wave of injuries and a packed schedule have seen the Revs go just 1-6-2 in all competitions since that win. In fact, the Revs' calendar has left them so tired that head coach Steve Nicol called his team's elimination from the CONCACAF Champions League "an absolute godsend."

Nicol added, "You can't compete if you can't run. It affects everything you do. We just need to get some rest."

MLS Primetime
Thursday Chivas USA at New England 7 p.m. ET (ESPN2, ESPN360.com)

2. The mentalist

Preki may not garner many Coach of the Year votes, but he should be commended for the way he has navigated his team through obstacle after obstacle. The latest of these was the apparent left thigh injury to goalkeeper Zach Thornton that occurred in last weekend's 3-1 win over Toronto FC. And while Preki refused to divulge Thornton's availability for Thursday's game, what's certain is that his team's mind-set won't change.

"It's been incredibly important, the mentality of the group," Preki said. "And the work rate, especially in the second half against Toronto … we've been sticking together on the field, and it's been very nice to see.

3. Ralston's return?

So depleted is Nicol's corps of attacking players that midfielder Khano Smith lined up beside Taylor Twellman at forward during last Saturday's 4-0 loss at Columbus. Yet the Revs could receive a boost ahead of Thursday's game in that playmaker Steve Ralston, who has been shelved by back spasms for the last two matches, could take the field.

"It would give us a huge boost," Nicol said of Ralston's possible return. "He's a big part of what we do, and he has a big influence on the team."

4. Chivas living on the edge

With the playoff race in the Western Conference impossibly tight, the importance of every game has become magnified for Chivas. The Goats currently occupy third place in the West, emblematic of the last guaranteed playoff spot, but they are also just four points away from last place. Yet this supermodel-thin margin of error hasn't fazed Chivas.

"I've got to give my group a lot of credit," Preki said. "We could have easily felt sorry for ourselves because of all the things that have been happening to us. But the group is finding a way to get the results, and that is all credit to them."

5. New England's tactical shift

So conscious has Nicol been of his team's heavy legs that he has switched to a 4-4-2 formation after playing a 3-5-2 for the last several years. The change hasn't been enough to stave off the team's recent struggles, but with Thursday's match set to be the team's 11th in the last 31 days, Nicol and Co. will continue to grit their teeth.

"When you play 3-5-2, physically it's tough on the wide guys and the back three," Nicol said. "Physically, we haven't been able to do it. It's just impossible, and never mind the fact that we've had so many games, it's also impacting the way we want to play. We haven't been able to put out the players we want to put out."

Five players to watch

1. Ante Razov, F, Chivas USA

In the last couple of years, Razov has had his own struggles with injury. But this year the former U.S. international has stayed healthy enough to come through countless times for the Goats, whether it was scoring vital goals or making the killer pass. Against Toronto, he did both, scoring a goal while adding two assists.

"Ante is a veteran, and he's been doing a pretty decent job for us," Preki said. "He's one of the most experienced guys we have on the field, and he's shown in the moments where you need to make a play or two that he's the one to make those plays."

2. Taylor Twellman, F, New England

Twellman missed much of the season with knee and ankle ailments, but lately he's been doing his best to keep the Revs afloat, as the five-time all-star has scored four goals in his last six league games. And with the end of the season fast approaching, Twellman appears to be hitting top form.

"Twellman isn't a problem at all; he's fit and ready," Nicol said. "He's one we don't have to worry about."

3. Jonathan Bornstein, D, Chivas USA

There was a time when Bornstein was firmly entrenched in the U.S. national team frame, but after spending much of this season on the sidelines, his name is now hardly mentioned. Yet in last weekend's win over Toronto, Bornstein took a big step forward, getting back to his attacking ways out of the back and scoring what would prove to be the game-winning goal.

"Any time you get injured, it takes a while to get into the flow of the games," Preki said. "Hopefully [Bornstein] can stay healthy and find his best form late in the season."

4. Jay Heaps, D, New England

With Nicol opting for a four-man back line, Heaps has been forced to take up a more central defensive role alongside Michael Parkhurst. The results haven't been all that convincing, with the Revs conceding eight goals in their last two competitive fixtures, yet Nicol wouldn't thinking of filling out his lineup sheet without Heaps' name on it.

"Heaps has been one of the stalwarts all year," Nicol said. "He's someone who is the backbone of the team. The drive he has, the enthusiasm; every game is a Cup final for him."

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5. Paulo Nagamura, M, Chivas

When captain Jesse Marsch sustained a broken jaw against Los Angeles on Aug. 14, it figured to be one injury too many for Chivas, given his importance to the team. Yet the Goats' midfield has held together, and Nagamura has been a huge factor in that regard, with his tackling and passing doing plenty to pick up slack.

Jeff Carlisle covers MLS and the U.S. national team for ESPNsoccernet. He also writes for Centerlinesoccer.com and can be reached at eljefe1@yahoo.com.