OK, several folks have asked me the same question: Will the Detroit Lions sign free agents to fill in the holes on the defense?

My answer: They already have.

With Martin Mayhew no roster is set in stone. At any point in the offseason or during the season if he gets a chance to upgrade a position, he’ll make the move.

He signed three defensive players as free agents this spring who not only have a good shot at making the 53-man roster — at least one of them could be a starter.

If you haven’t been paying attention, here are the Lions three key defensive signings so far:

1. Safety James Ihedigbo (in photo) is penciled in (at least by me) as a starter along with Glover Quin. He’ll replace Louis Delmas who was signed by the Miami Dolphins.  Ihedigbo played for Lions defensive coordinator Teryl Austin for the Baltimore Ravens the past two seasons. Austin was the secondary coach and obviously knows Ihedigbo well. In fact they both earned Super Bowl rings while there. Ihedigbo, 30, started all 16 games for the Ravens in 2013 with three interceptions, 11 pass defenses, two forced fumbles and 101 tackles. It was the first time in his six-year NFL career that he started 16 games. He’s a natural leader, couldn’t be happier to be reunited with Austin. Watch him.

2. Defensive end Darryl Tapp, 29,  has a history with Austin that goes way back to when they were in Seattle in 2006 — Tapp was a rookie and Austin was the defensive backs coach. Tapp was with the Washington Redskins in 2013, the only season he lined up as a linebacker playing in a 3-4 defensive scheme. He’s happy to be back to the 4-3 and back with Austin. His numbers were down in 2013 because he was playing an unfamiliar position. In three seasons with the Philadelphia Eagles (2010-2012) he had six interceptions. Look for him to rotate in along the defensive line and play on special teams.

3. Cornerback Cassius Vaughn, 26, doesn’t have an Austin connection but he’s young and durable. He played in all 16 games each of the last two seasons with the Indianapolis Colts, getting 15 starts in that span with four interceptions and 15 pass defenses. He’ll compete for time at cornerback and   he also has extensive experience on special teams. In the OTA that was open to the media last week, Vaughn was a standout on defense. Oddly enough in November 2012 he was fined for a late hit on then-Dolphins running back Reggie Bush. 

So there you go. The defense, which ranked in the middle of the pack in the NFL in 2013, has been addressed in the draft and free agency.

Perhaps Ihedigbo, Tapp and Vaughn are not flashy NFL names, but they could be contributors this season.

(Follow @PaulaPasche on Twitter. Order her book,  “100 Things Lions Fans Should Know & Do Before They Die’’ here. It’s also available at bookstores.)