The Portland Timbers are in a bit of a bind as they head into the first leg of their Western Conference Final matchup against FC Dallas next Sunday; starters Diego Valeri and Rodney Wallace will be forced to sit out the match after each picked up their second yellow card of the playoffs in the team's 2-0 road win over the Vancouver Whitecaps to clear the Conference Semifinals.

The match against Dallas will not be the first time that the Timbers have had to shuffle up their lineup this season after a year rife with injuries. Wallace has been in and out of the starting lineup and Valeri has spent the year coming back from a torn ACL and subsequent rolled ankle that kept him from his top form for much of the season -- and saw him just barely miss out on winning Comeback Player of the Year honors. Still, both players have been key to the Timbers' recent run of rampant form, as the team have gone 6-1-1 over their last eight matches.

So, what gaps will the Timbers have to fill in the absence of Valeri and Wallace? As the Timbers have changed the team's set up in recent matches, moving to a single holding midfielder rather than the double pivot that has been the norm for much of the last three years, the front four have become more clear in their responsibilities rather than the free-flowing positioning that we saw previously. Wallace, despite switching flanks with some regularity, has played as an out and out left winger, while Valeri has maintained his no. 10 spot at the heart of the attack, roaming anywhere in the attack.

Replicating the specific contributions of the pair seems unlikely with the players currently available -- the Timbers have no out and out no. 10 replacement and the team is decidedly limited in their selection of wingers as well -- but the team's depth could certainly be brought to bear in a new set up.

So, let's take a look at some possibilities for the Timbers and what they could mean for their approach to the match.

Melano looks like the most likely player to step back into the Timbers' starting lineup against Dallas and, having spent most of his recent matches out wide on one wing or another, he will almost certainly line up out wide once again. On the wing, Melano brings a very different skill set from Wallace, often looking to get forward and get in behind the opposition back line from the right or cut in toward the center of the pitch while on the left.

Wallace's commitment to defense is one of his defining characteristics as a wide midfielder; Melano does not have the same level of defensive quality, but does at least put in the work, tracking back and breaking up opposition plays through sheer athleticism and doggedness.

Although it is possible that Melano could line up just about anywhere in the attack for the Timbers, his recent appearances on the wing seem to make this the easiest change for the Timbers to make.

Forget the ongoing muttering about Johnson's future with the team: it might just be time for the return of Will Johnson to the pitch for the Timbers. In the absence of Valeri, it seems likely that Darlington Nagbe will be pushed further up the pitch to facilitate the attack, rather than the more deep-lying role that he has settled into recently. With Nagbe less available to drop back into the space just above the back line, the Timbers may look to make a return to their old double pivot set.

Johnson is not the straight up favorite here, however. Both Jack Jewsbury and George Fochive should be available for this one and could easily step in rather than Johnson. Fochive seems like the less likely of the two to line up alongside Diego Chara after several sub-par matches from that pairing, including the season finale against the Colorado Rapids when Fochive looked extremely out of his depth until Chara was forced off with an injury and Jewsbury stepped in, immediately changing the game for the Timbers' midfield. Unlike Fochive, however, Jewsbury has played well alongside Chara all year, including several matches late in the season.

So, why would the Timbers put Johnson in? Well, despite not seeing much playing time with the Timbers recently as he comes off a minor surgery to remove several screws from his leg, Johnson played a combined 161 minutes for Canada against Honduras and El Salvador over the international break, getting an assist in the process. Moreover, with Valeri out, the Timbers will need a player able to spread the ball around the field from the center of the pitch and Johnson is certainly that.

The Timbers are not limited to a single forward against Dallas. Maximiliano Urruti may not have been able to replicate the goal scoring highs of 2014 season, but his creativity and propensity for drifting off the back shoulder of defenders should mesh well with the hold up play of Fanendo Adi. That has not always been the case when the two have lined up together at the top of the Timbers' formation, but we have seen Urruti score goals in bunches previously and, like the rest of the Timbers, there is a nagging feeling that output of that kind is still possible from the Argentine.

Who do you think will see the field on Sunday?