Running back sensation Eddie Johnson reported for his senior season at Utah this week and, at least so far, he has put to rest concerns about his reconstructed knee.

Now he's got another problem _ his aching back. Johnson's been bothered by a mysterious back ailment, not bad enough to put him down, says trainer Bill Bean, but enough to irritate him.

"We don't know what the problem is," said Bean. "Nobody does." Johnson has seen numerous doctors and specialists and so far all test have come in with the same diagnosis: no apparent problem. The Ute staff doesn't know how Johnson hurt his back, but Bean says it is likely that his months of going around on crutches, then the sudden activity, may have done it.

However, Johnson seems improved since two-a-days began last Saturday.

Meanwhile, the Utes are excited about the prospect of Johnson's knee being well again. "Eddie's not hobbled," said Coach Jim Fassel. "He's making the cuts. I'm really pleased with the way Eddie looks." The big question, says Bean, is how long Johnson can run on the rehabilitated knee, once he gets into game situations.

CLEAN BILL: It is still premature, but already Fassel is seeing signs of improvement in the injury area. At this stage a year ago, a half-dozen players were already out for the year. This year, only defensive end James Thompson is hurt. Thompson, a projected starter, tore some cartilage in his knee jumping rope but expects to be back in two or three weeks.

Fassel credits the improved injury record to a strong off-season weight and conditioning program.

FAST COMPANY: Last weekend, while watching photos being taken of the incoming freshmen, Fassel couldn't help but exclaim to himself, "Um. Gooood-looking class."

He has reason for optimism. The Utes signed four freshman players who were invited to the prestigious California Shrine prep all-star game last month. It was the same number of Shrine players as Southern Cal signed, and second to only one other team in the nation _ UCLA.

The best news for the Utes is that three of the players are defensive specialists. The list includes defensive back Derek Odom, tackles Brian Anderson (6-7, 240) and Bascom Mellon (6-3, 265) and running back Steve Abrams.

BIG MAN: Utah's 6-foot-6, 230-pound quarterback Scott Mitchell is apparently impressing people in a way befitting his stature. Air Force Coach Fisher DeBerry and Wyoming Coach Paul Roach both referred to Mitchell as "a good-looking tackle."

But UTEP quarterback Pat Hegarty went one better. Here is how he describes his impressions when he first saw Mitchell at last year's Utah-UTEP game in Salt Lake:

"Six-six and 230," says Hegarty. "Whew! He comes in off the bench in the cold rain. He's not warmed up or anything. He steps up and throws it 65 yards in the air on the first pass. He overthrew the receiver, but still, I just said to myself, `Now that's a man!' "

LAND HO! The face is familiar, but . . . One of BYU's new coaches is a volunteer assistant from New Mexico State named Land Jacobsen.

If the name, or face, is familiar, it should be. Jacobsen coached the defensive backs at Utah under Chuck Stobart in 1983 and