The temptation is for the Union to use all their offensive weapons from the beginning, looking to wipe out that one-goal deficit, although one thing that will be considered in making out the lineup is size, or lack of it, for the Union.

First the particulars.

After losing, 2-1, in Sunday's first game of this two-game aggregate goal series to the Houston Dynamo, the Union need to win by at least one goal in 90 minutes of regulation during Thursday's game at Robertson Stadium.

If the teams are tied in aggregate goals after the 90 minutes, two 15-minute overtimes will be played in their entirety. If tied after that, the matter will be settled by penalty kicks.

Nobody wants penalty kicks, but the Union would take it over the alternative. Either way, it will be interesting to see how soon the Union go on the offensive.

In Sunday's loss, the Union's three substitutions were all used to spice up the offense in a game in which they trailed, 2-1, after Houston's Calen Carr broke a 1-1 tie in the 30th minute.

Jack McInerney entered in the 62d minute, followed by Roger Torres in the 68th minute and Freddy Adu in the 76th minute.

All brought energy to the attack, and McInerney almost provided more, hitting the crossbar on a header in the 88th minute off a feed from Adu.

All three are known more for their offensive skills, Union assistant coach John Hackworth said, but it would be tough to start all three in the beginning of the game.

See, Torres is 5-foot-5. Adu is listed on one roster as 5-6 and another at 5-8, and he may be neither. McInerney is the towering figure among the trio at 5-9.

"Houston scores over 40 percent of its goals on restarts and there is a big size advantage if Roger, Freddy or even Jack is in there," Hackworth said. "You are losing some serious battles."

That may be true but McInerney had enough hops to get to that header that hit the crossbar.

It's true that Houston is ever so dangerous in the air, evidenced by its first goal when Brad Davis, who may be the most dangerous and accurate passer in MLS, found teammate Andre Hainault on a free kick from 40 yards out. The 6-foot Hainault did the rest, heading it in.

Still, the Union have the players in the back line to win balls in the air.

What Torres and Adu in particular do is put pressure on the defense with their one-on-one ability.

Torres has even started shooting more recently because teams are playing off him a little, afraid that he can break down defenders with a single move. The next step is finding more accuracy on those shots.

As for Adu, it may be time to give him a full game to display his talent. While he won't be nominated for MLS defensive player of the year anytime soon, sometimes a team has to ride a player's attributes, which in Adu's case is the ability to make life miserable for opposing defenders.

In his 11 regular-season games with the Union, Adu played the full 90 minutes just once, in a 4-4 draw with New England.

The fact that it was the Union's second-best scoring output of the season is probably no coincidence. Adu scored a goal in that game.

"Freddy is a difference-maker for us," Hackworth said.

And now it's time to put that difference-maker on the field from start to finish, sacrificing a little size and defense for a player who clearly has the ability to help wipe out that one-goal deficit.