INDIANAPOLIS — The New England Patriots’ Wes Welker and the New York Giants’ Victor Cruz were two of the NFL’s most productive wide receivers this season, and their teams expect them to play critical roles here Sunday when the two clubs square off in the Super Bowl.

They have something else in common as well. Each entered the league as an undrafted free agent.

Victor Cruz (Jeffrey Phelps — Associated Press)

Drafting wide receivers is a notoriously risky proposition for NFL teams. A long list of receivers taken in the first round over the years have not worked out. Cruz and Welker represent the other side.

Welker’s 1,569 receiving yards ranked second in the league this season behind only the 1,681 yards by Detroit’s Calvin Johnson, a prized first-round pick who actually has lived up to expectations. Cruz’s 1,536 receiving yards ranked third.

“It’s a very fine line,” Cruz said. “It takes a little bit of luck. It takes a lot of skill and a lot of determination, a lot of hard work…. It’s being in the right place at the right time, being with the right team, being at the right moment and making all the necessary plays when you have to.”

Cruz is in his second NFL season out of the University of Massachusetts. His 82-catch season came after he had no catches for the Giants as a rookie last season, when he played in three games.

Wes Welker (Charles Krupa — Associated Press)

Cruz must hope he can sustain his success as Welker has. Welker’s 122 catches for the Patriots this season gave him four seasons with more than 110 catches per season in his five years in New England.

But nothing was handed to Welker during an NFL career that began when he was signed by the San Diego Chargers in 2004 as an undrafted rookie from Texas Tech. Welker made the Chargers’ roster but was waived after one game. He was signed by the Miami Dolphins. He had no catches for either team as a rookie.

But his 29-catch second season and 67-catch third season in Miami caught the eye of the Patriots, who traded second- and seventh-round draft choices to Miami in March 2007 for Welker.

“Trust me, I take nothing for granted as far as football goes and as far as my career, and understanding that you never know when your day is up,” Welker said this week. “They can cut you at any time.

“I remember back then, I made the team and being a rookie, I didn’t know that they could cut you in the middle of the season after that. The next week, I was cut. It was definitely a very humbling experience for me. But hopefully I don’t relive that again.”