Injuries, a crowded schedule and a fired-up opponent lying in wait.
You couldn't fault Toronto FC manager Ryan Nelsen for cringing at the prospect of a hot, humid summer night in Houston. But Nelsen is looking forward to seeing his revamped lineup stand up and be counted in Saturday's MLS rematch with the Dynamo (9 p.m. ET).
Nelsen will be counting on 21-year-old defenders Doneil Henry and Nick Hagglund.
Henry, who made his league debut in 2010, is a gifted athlete who is raw and still prone to mistakes. But his upside is immense and some see him as a future captain of Canada.
Hagglund is a likable, athletic rookie who seems comfortable on any stage. Fearless is one adjective applied to him.
"It's kind of exciting, to tell you the truth, to watch these guys playing and watch these guys progress," Nelsen said after training Friday.
"It's fun watching these guys, especially like Nick and Doneil, progress as players and as humans."
Thanks to a tour de force performance from England striker Jermain Defoe, Toronto (7-5-4) rallied from two goals down last Saturday to defeat Houston 4-2 at BMO Field. The Dynamo (5-11-3) have had all week to plan their revenge while Toronto, which has twice as many games this month as Houston, had a midweek encounter with the visiting Whitecaps.
Bleak injury prognosis
That 1-1 tie left its mark, with Nelsen revealing the bleak injury prognosis Friday before flying to Texas.
Fullback Mark Bloom, who has started all 16 games this season, is out four to six weeks with a medial collateral ligament sprain. Brazilian winger Jackson will be out 10 to 14 days with a knock to the Achilles.
They join captain Steven Caldwell on the sidelines. The Scottish centre back tore his quad in the win over Houston last weekend and is expected to be out for a month.
Veteran Bradley Orr, a useful jack of all trades this season, replaced Caldwell against Vancouver and is expected to line up alongside Henry again Saturday. Hagglund, normally a centre back, will start for Bloom.
"I'm going to try and do my best Mark Bloom impression when I'm on the field," said Hagglund.
Dominic Oduro could join Canadian Jonathan Osorio and the central tandem of Michael Bradley and Collen Warner in midfield.
Toronto will be hard-pressed if another defender goes down. Jackson would have been one of the candidates to replace Bloom if healthy.
Nelsen only has fullback Ashton Morgan in reserve. Starting left fullback Justin Morrow can play centre back in a pinch. Fullback Ryan Richter, currently on loan to Ottawa Fury FC, could be recalled next week for cover.
Injury issues aside, Nelsen anticipates a rough reception in Houston.
"I expect a very motivated, bordering on vicious to tell you the truth, Houston team," said Nelsen. "They have to win, they have to win in front of their fans. They have to win to get their season (going).
"They've had injuries. That's what they've kind of hung their hat on, that it hasn't been a successful season (as a result). Now everybody's fit. It's a make-or-break game. We understand that. We can't match that, we have to better it."
Veteran midfielder Dwayne De Rosario, who spent three seasons in Houston, also expects a spirited response from the Dynamo.
"If there's one thing that I know, it's that Dominic (manager Dominic Kinnear) is very good at is turning the team around," he said. "Definitely I think you're going to see a much more physical, much hungrier, more tenacious team come (Saturday)."
Added Hagglund: "It's gut-check time."
The good news for Toronto is that it stands third in the Eastern Conference with two or three games in hand on each of the four teams around it. And it has lost just one of its last nine games (a 4-1-4 run).
Houston is winless in seven games, a stretch that has seen the Dynamo outscored 19-4. Houston's last league win was May 17 against Columbus.
The Dynamo, however, are returning to full strength after the World Cup and injuries,
Left back Corey Ashe (knee) may be the latest to come back. Midfielders Brad Davis and Boniek Garcia (both at the World Cup) and defenders David Horst (groin) and Jermaine Taylor (hip contusion) have also returned to the lineup.
Houston is looking to erase memories of the wasteful Toronto loss.
"There's obviously a bad taste in our mouths from the way things went," goalkeeper Tally Hall told reporters in Houston.