The Buffalo Bills and 31 other NFL teams are about to do some window shopping.

They won’t make any immediate purchases, but they’ll have a good idea what to pick up later on.

On display for the team’s perusal will be more than 300 college football players invited to the annual NFL Scouting Combine, which will run Thursday through Sunday in Indianapolis. The venue has moved from the RCA Dome to Lucas Oil Stadium down the street.

The site has changed, but not the objective. Top executives, coaching staffs, player personnel departments and medical personnel will be on hand to evaluate the nation’s top college football players eligible for the upcoming NFL draft.

The players will go through a battery of drills to test their speed, strength and overall athletic ability. Each player will be weighed and measured and examined thoroughly by team doctors. The teams also will conduct 15-minute interviews with selected prospects.

Bills Chief Operating Officer Russ Brandon said the combine is just “one piece of the puzzle” in the evaluation process.

“Their body of work is the main focal point,” he said. “But certainly the combine gives us an opportunity to add variables into the mixture from the standpoint of not only the interview but just see how they react in their position drills. Then you layer that on their body of work that you have already compiled over the past year.”

As is the case every year, the teams will have to deal with players who chose not to work out for whatever reason. One prospect who has already announced he won’t work out is Texas Tech wide receiver Michael Crabtree, a projected top-10 draft pick who isn’t running because of a right ankle sprain suffered during the Cotton Bowl in January. Georgia’s Matthew Stafford, who is competing with Mark Sanchez of USC as the top quarterback, is not expected to throw.

A lot of players wait until their on-campus workout, called “pro days,” where they can display their skills in an environment they can control. But the combine takes on more importance in a bad economy that may limit teams’ ability to travel all over the country to watch guys run, lift and jump.

“I sometimes cringe at all the travel we have to do,” said Tom Modrak, the Bills’ vice president of college scouting. “It is a necessary part of the business, but I think [the economy] will slow it down and should slow it down. That’s why it’s important for guys to work out. You can still have your pro day. But if you can run and jump at the combine, don’t be afraid to do so.”

Modrak added that the combine isn’t a pass-or-fail proposition. If a player doesn’t perform well, it doesn’t necessarily hurt his draft stock. But there will be players whose rating will soar as a result of a good showing in Indy.

All eyes will be on the top prospects like Sanchez, who could gain on Stafford if he throws well. With Crabtree out of the mix, receivers like Jeremy Maclin of Missouri and Percy Harvin of Florida could move up the charts if their 40-yard dash times are as fast as expected.

Brandon Pettigrew of Oklahoma State is the consensus choice as the best tight end in the draft. A good combine showing would likely confirm that.

Underclassmen running backs Chris “Beanie” Wells of Ohio State and Knowshon Moreno of Georgia have enhanced that position.

Offensive tackle is one of the deepest positions in the draft, according to draft experts. Big men like Baylor’s Jason Smith, Alabama’s Andre Smith and Virginia’s Eugene Monroe are looking to solidify early first-round grades.

Is California center Alex Mack the top-ranked interior offensive lineman or will Oklahoma guard Duke Robinson or Oregon center Max Unger surpass him?

On defense, Aaron Curry of Wake Forest leads a good looking group of outside linebackers that also includes Brian Cushing of USC.

Aaron Maybin and Larry English were explosive defensive ends at Penn State and Northern Illinois. This week, they will get a chance to show if they can convert to linebacker at the pro level.

Defensive ends Brian Orakpo of Texas, Everette Brown of Florida State and defensive tackle B. J. Raji of Boston College will be among the defensive linemen on display.

Ohio State’s Malcolm Jenkins and Illinois’ Vontae Davis will battle for the title of best cornerback. USC’s Rey Maualuga and Ohio State’s James Laurinaitis are the top-rated inside linebackers.

The University at Buffalo will have a combine participant for the third straight year. Quarterback Drew Willy was invited to Indianapolis. Center Jamey Richard went last year and tight end Chad Upshaw participated in 2007.

The Bills have needs at outside linebacker, tight end and interior offensive line, but they aren’t going to limit their focus to a handful of positions.

“We’re looking for the best football player that we can add to the roster,” Brandon said. “We go in with a very open mind and look at the full complement of people out there. You have to approach it with a very wide lens.”

“You get yourself in trouble when you say, ‘Well, if we don’t have one of these our draft is a failure,’ because it might not be the right time to take one of those,” Modrak added. “You better find a good player, players who are going to help your team and over the long haul you’re going to be better off. If you do it the other way, I think that’s short term. You’re putting a patch on a tire that comes off pretty soon.”