At the Marquette practice facility, Jermaine Marshall on Wednesday took a pass near the key and didn't hesitate, launching a 3-pointer that touched nothing but net. His Arizona State teammates rushed over to pat the senior guard on the back.

As ASU enters its first NCAA Tournament in five years, the 10th-seeded Sun Devils need the scene to repeat in Thursday night's second-round matchup against No. 7 seed Texas. With Marshall hitting from the perimeter, they are a different team, and it's not a stretch to say their tournament success rests on his streaky jump shot.

"He's huge," sophomore point guard Jahii Carson said. "He's able to space out the court for us. He's able to knock down shots for us, and teams have to pay attention to him. That makes it easy for the big fellow (senior center Jordan Bachynski). He doesn't get trapped as much. It's easy for me to get into the paint because teams don't collapse as much. He's just about as big on the team as anybody."

Problem is, Marshall's jump shot has vanished. A 40-percent 3-point shooter, he has missed 17 of his last 21 3-point attempts. Over ASU's past three games — losses to Oregon, Oregon State and Stanford — Marshall has shot 4 of 14, 1 of 12 and 2 of 8 from the field. As a result, the Sun Devils have limped rather than surged toward March Madness.

This could be a health issue. Marshall — ASU's second-leading scorer at 15 points per game — has battled knee issues throughout his career. He tore his patella tendon his senior season of high school and needed surgery. Since then, through three seasons at Penn State and this season at ASU, the injury has required preventative maintenance. Throughout this season, it wasn't uncommon to see the Sun Devils practicing while Marshall shot free throws off to the side, especially the day after a game.

Marshall said this week he feels fine, but he hasn't looked it. He doesn't seem to move as well as he did earlier this season, when he hit some of the biggest shots of ASU's season. On Jan. 29, Marshall hit a 3-pointer in the final minute to force overtime against California, a game the Sun Devils won. Sixteen days later, he scored 29 in an upset win of Arizona to earn Pac-12 Player of the Week honors.

Since then, with the exception of a two-game scoring burst at home, Marshall mostly has struggled, and so have the Sun Devils, losing five of seven since celebrating the Arizona win on Valentine's Day.

"A lot of the ones I'm missing are wide open," Marshall said. "I've had some wide-open looks. A couple of them I felt like I was trying to guide the ball, but the other ones are rolling around, in and out of the basket. There's not much you can do about those."

To try to regain his touch, Marshall estimates he has put up 350 to 500 extra shots a day since the end of last week's Pac-12 Tournament. On Monday, he stayed after practice with assistant coach Stan Johnson shooting jumpers around the arc, with Johnson reminding the guard to focus on three things:

• Being long on his shot and not short.

• Getting his elbow to eye level rather than nose.

• Staying with the shot after the release, landing in the same spot every time.