It started as an experiment in the spring.

The Eagles were thin at safety, so they moved cornerback Walter Thurmond there. The five-year veteran had never seen a snap at safety since he entered the league. But he was a slot cornerback, so he was used to lining up on the inside of the formation.

Coach Chip Kelly has praised his performance at safety since he made the switch. It seems he's picking up on his new position quickly.

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"[He's been] very productive. If you watched him Sunday at The Linc, I think he had two interceptions and caused a fumble. I think he leads the defensive backs right now in turnovers caused, whether it be interceptions or fumbles caused," Kelly said of why he likes Thurmond at that position. "He just kind of has a knack of being around the ball. I think he’s a real savvy player back there, has fit in real well, has been kind of seamless for him in that transition from corner to safety. But he just always seems to be around the ball making plays.

Though safety is new to him, the principles remain the same. One difference Thurmond was noted is that his new home requires more patience — he's not in the middle of the action as consistently as a cornerback.

"There's a lot of similarities within the coverage and scheme to where if I was playing nickel, I would be playing a lot of the same techniques as a safety would," Thurmond said, via CSNPhilly.com. "The only difference is playing the middle of the field and some of the quarter and half techniques we have as well."

Related: Four Eagles players who could step in at slot cornerback

After rookie cornerback JaCorey Shepherd tore his ACL on Sunday, Kelly floated Thurmond's name as a candidate to step in at nickel corner. It's certainly possibly he sees time there, but the Eagles have far more options at that spot than at safety. The oft-injured Earl Wolff is Thurmond's primary competition for the starting safety spot alongside Malcolm Jenkins. Meanwhile, rookie Eric Rookie, Jaylen Watkins and E.J. Biggers could all play the slot.

That's why the best plan is probably to keep Thurmond at safety. It's all part of a revamped Birds secondary that should be much better than the one that allowed 264.9 passing yards per game last year (second-most in the NFL).