The hard-luck Trail Blazers encountered more injury heartbreak Thursday, when two players were lost for the season and another was lost for at least one game.

to bolster the Blazers' rail-thin frontcourt, retired suddenly because of a preexisting heart condition.

Rookie guard Elliot Williams elected to have season-ending knee surgery.

And, as if that weren't enough, reserve guard Rudy Fernandez sat out because of a sore back.

Thirteen players missed a combined 311 games last season because of injury or illness. Six games into the season, the team is on pace to set or eclipse that mark.

"My phone is on me at all times," coach Nate McMillan said, joking, as if he were awaiting word of another injury. "I really don't know what to say. It's a shock."

Oberto experienced dizziness and light-headedness during

, symptoms of "recurrent palpitations related to a prior cardiac condition," according to the team. After talking Wednesday with his family in Argentina about his situation, Oberto decided "to put my health and my family in front of basketball," and retire.

The Blazers signed the veteran center the morning of the regular-season opener only because they were desperate for frontcourt help while they await the return of injured centers Joel Przybilla and Greg Oden.

. Suddenly, the team is back to Square One.

General manager Rich Cho plans to evaluate five players today in hopes of finding an immediate replacement for Oberto, who had played in five games with the Blazers:

Sean Marks, a 10-year veteran who played for New Orleans last season; Arizona State graduate Eric Boateng, who played with Denver during training camp; Dwayne Jones, a five-year veteran who played for Phoenix last season; Earl Barron, a four-year veteran who last played with the New York Knicks; and former Blazer Shavlik Randolph.

While the loss of Williams doesn't sting as much as the loss of Oberto, it is yet another blow to the franchise. Williams is expected to have surgery next week to repair a dislocated right patella and will miss the rest of the season.

Williams said he's had the injury -- in which his knee cap essentially pops in and out of its socket -- since high school and it was the reason he shut down private workouts during the predraft process over the summer. The Blazers knew about the condition when they drafted him, but downplayed concerns even though they held him out of summer league play.

Williams re-aggravated the injury Wednesday during a workout at the practice facility. After an examination with team doctors, he and the Blazers decided it was best to have surgery now.

and had not yet played in a game, said he expects to miss between four and five months.

"It's a minor thing, but it just felt like the time to get it fixed," said Williams, who walked normally around the Rose Garden before Thursday night's game against the Oklahoma City Thunder. "It's just something you don't want to have to keep dealing with because something major could happen down the road."

As two Blazers were lost for the season, another was lost for at least one game. Fernandez, who had microdiscectomy surgery and missed 20 games last season with an injured back, was a late scratch Thursday because of a sore back. It was not immediately known how much time he will miss.

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