The predicament facing USC became clear with 9 minutes 32 seconds left in the second half Thursday night when into the fray trotted sophomore Ryan Wetherell.
As in walk-on guard Ryan Wetherell.
A hip injury in the opening minutes had rendered sophomore guard Daniel Hackett unavailable, and freshman guard Marcus Simmons, one of only two perimeter substitutes, wasn't an option because he aggravated an ankle injury earlier in the week and may be out for the season.
Short-handed USC hung tough against Arizona before fading over the final four minutes of an 80-69 loss at the Galen Center in front of record capacity crowd of 10,258.
"We're not going to use that as any kind of excuse," USC Coach Tim Floyd said of the absence of Hackett, who was taken after the game to a hospital for precautionary X-rays. "This was a game that was going to be difficult to win with or without Hackett."
Floyd said there were concerns Hackett had chipped a bone in his hip or broken a rib.
"That's the worst-case scenario," Floyd said. "We'll hope for something better."
Even without Hackett, who was coming off a career-high 26-point performance against Oregon, the Trojans were in a position to win when they took a 56-55 lead with 7:23 remaining on a free throw by sophomore forward Taj Gibson.
But several breakdowns cost USC over the final minutes.
The Trojans couldn't grab the rebound on two missed Arizona free throws and then failed to secure the ball after twice stopping the Wildcats on the defensive end.
"We just didn't rebound the ball well and it hurt us," Gibson said.
The Trojans fell to 13-7 overall and 4-4 in the Pacific 10 Conference despite shooting 50% to Arizona's 48.3%, extending USC's streak of shooting better than all eight conference opponents. Trojans freshman guard O.J. Mayo scored 23 points on nine-for-23 shooting.
Sophomore forward Chase Budinger scored 29 points and senior guard Jawann McClellan had 23 for the Wildcats (15-6, 5-3), who won their fourth consecutive game while ending USC's four-game winning streak.
Arizona, which trailed by as many as six points early in the second half, went ahead for good on a putback by sophomore forward Jordan Hill with 6:47 remaining. A three-point shot by Budinger and a baseline jumper by McClellan following an offensive rebound extended the advantage to 62-56.
Wildcats sophomore guard Nic Wise made it 71-61 when he made a three-point shot with 2:48 to go, twirling his body in glee on his way down the court.
The Trojans played all but the first 1:45 of the game without Hackett, who grimaced in pain after diving to the floor in an attempt to keep a ball from going out of bounds along the baseline.
Hackett left the game immediately and was taken to the locker room before returning late in the first half and sitting in the row directly behind the team bench. Gibson said he could quickly tell Hackett's injury was serious.
"I knew immediately as soon as I looked at his face," Gibson said. "I saw he was real emotional and I saw too many ice packs."
USC's Angelo Johnson had seven points and six rebounds in 37 minutes off the bench, and Wetherell did not score in five minutes but did draw an ovation when he tied up Wise for a jump ball.
"The guys off the bench came in and competed hard, we just came up short," Mayo said.
USC wilted in part because it made only one of 11 three-point shots in the second half.
"We didn't have that additional shooter to knock it down tonight," Floyd said.