LUBBOCK, Texas (AP) -For the first time in Texas Tech coach Mike Leach's tenure, there's no Red Raiders quarterback anywhere on the national list of top passers heading into Saturday night's game against Texas A&M.

The quarterbacks in charge of No. 21 Texas Tech's high-octane offense this year - starter Taylor Potts and backup Steven Sheffield - can't stay healthy.

Leach, whose quarterbacks at some point in every one of his nine seasons have led the nation in passing, won't reveal who'll start against the Aggies, who are trying to end a three-game skid.

``We wouldn't have it any other way,'' Leach said of his game-day decision.

The Red Raiders (5-2, 2-1 Big 12) moved into the rankings for the first time this season after winning 31-10 at then-No. 15 Nebraska last week. Sheffield, the backup QB in his second career start, threw for 234 yards and one touchdown.

He also ran for two TDs but hobbled off the field, apparently with an injured left foot. Potts, who led the nation in passing earlier this season, suffered a concussion before halftime in an Oct. 3 win over New Mexico.

Leach does not acknowledge or comment on player injuries.

The two QB's stats together - Potts has 13 TDs and 1,817 yards; Sheffield has 12 TDs and 1,014 yards - would surpass the nation's top passer, Case Keenum of No. 17 Houston. Keenum has 19 touchdowns and 2,501 yards; Potts and Sheffield have 25 TDs and 2,831 yards.

Aggies coach Mike Sherman said it doesn't matter who quarterbacks Texas Tech.

``They have a great system out there,'' Aggies coach Mike Sherman said. ``They plug 'em in and out in a lot of positions.''

Leach mentioned Colorado and Purdue as teams that beat ranked opponents last week and that no one on his now-ranked team should look past the Aggies.

``In this conference you have to respect everybody. There's nobody that isn't good enough to beat you,'' Leach said. ``I suspect that (the Aggies) will come out swinging.''

Like Potts and Sheffield at Texas Tech, A&M had a little QB competition of its own before the season.

Jerrod Johnson won the starting spot over Ryan Tannehill, who played receiver last season.

In last week's 62-14 loss to Kansas State, Johnson set a school record with his fourth 300-yard passing game of the season. He threw a Big 12 record 225 passes without an interception before throwing three against the Wildcats.

Johnson still leads the Big 12 in total offense (342.5 yards per game) and touchdown passes (16) and ranks second in passing (315.5 yards per game).

Sherman believes Johnson's leadership approach will serve the Aggies well against the Red Raiders.

``I think he's been very effective doing it that way,'' he said. ``He will do what it takes. I don't think his personality is such that he's going to yell and scream at guys.''

Texas A&M (3-3, 0-2 Big 12) had the nation's top offense through its first three games, averaging 574 yards. Facing better defenses the last three weeks, the Aggies have averaged 380 yards in three losses.

A&M has been running a no-huddle offense designed to wear down opposing defenses this season. They rank second in the nation in offensive snaps per game (83.5).

Sherman has been moving around offensive linemen to compensate for injuries and inexperience. The Aggies have allowed 12 sacks in the last three games, compared to only four in the first three games.

A&M will face another active defense Saturday, as the Red Raiders are eighth nationally in sacks (23, with 3.3 per game). Brandon Sharpe, a Big 12 defensive player of the week after his four sacks at Nebraska, has eight for the season, tied for fourth nationally.

Sharpe has gotten seven of his sacks in the last three games.

The Red Raiders defense, frequently a question mark, impresses Sherman.

``They play good, solid defense,'' Sherman said. ``They play their system, they believe in their system, and they match up on your routes pretty good.''