CHESTER, Pa. – Sheanon Williams has been the Philadelphia Union’s starting right back since the franchise’s inaugural season in 2010, and last year became the first player to play in 100 games for Philly.

But, at this moment, the 24-year-old no longer considers himself as a starter – not when he’s yet to play a game this season and Ray Gaddis has played every minute at right back.

“Ray, right now, is the starter,” Williams told MLSsoccer.com. “Right now, I’m the backup. He’s been playing well. Obviously I give him all the credit in the world. I always try to encourage him and he’s been doing great.”

Williams found himself in this situation after slipping as he hit a cross in the second-to-last game of the preseason – a scoreless draw with Toronto FC on Feb. 26 – and “hearing a pop.” He was diagnosed with a partial tear of his right quad and given a five-to-six week timetable to return by the training staff.

Williams said he returned to training last week but this week was the first time he felt “pain free.” Still, it doesn’t look particularly promising that he’ll make his season debut this Saturday when the Union face the Chicago Fire at Toyota Park (5 pm ET, MLS LIVE).

“He’s finally 100 percent in training,” Hackworth said of Williams. “He went through everything. But you have [left back] Fabinho and Ray Gaddis who have played well through the first month of the season, so Sheanon’s got his work cut out to get back into the starting lineup.

“Sheanon is somebody that we think we need to go forward, but obviously it’s really nice to have the depth that we’re having and to have guys play well.”

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Hackworth is currently dealing with a similar situation at center back, where Austin Berry is returning from a hamstring injury but will have a hard time unseating Aaron Wheeler in the starting role.

And both Berry and Williams seem to understand that nothing is a given when it comes to the team’s starting lineup.

“If that was me, I wouldn’t want to get yanked from the lineup,” Williams said of Gaddis. “He wants to start and play every game and the same goes for me. But right now he’s playing well and the team’s playing well.”

Williams also recognizes that he needs to get his fitness back before he can be as effective as he’s been over the past three-plus seasons for the Union.

But even then, regaining his place in the starting lineup is far from a sure thing.

“I think this year we have more depth than we’ve had before and we have guys fighting for every position,” Williams said. “Competition makes for a good team and pushes the guys in front of you. Right now, I’m just going to push Ray to try to do his best.”

Dave Zeitlin covers the Union for MLSsoccer.com. Email him at djzeitlin@gmail.com.