OWINGS MILLS, Md. -- Baltimore Ravens offensive lineman John Urschel announced his retirement before the start of training camp Thursday, an abrupt decision that shocked many.

Considering how the Ravens' offseason has gone, should anything be a surprise?

Since June 1 -- a span of 57 days -- the Ravens have lost five significant players for this season:

Tavon Young, a starter last year and a promising nickelback, tore his ACL on June 1.

Dennis Pitta, who led all tight ends with 86 catches last season, suffered a likely career-ending hip injury on June 2.

Darren Waller, a special-teams standout and a backup tight end, was suspended for the year on June 30 for violating the NFL's substance abuse policy.

Kenneth Dixon, the team's most elusive running back, underwent season-ending knee surgery on Tuesday.

Urschel, who was competing for the starting center job, told the Ravens he was retiring Thursday morning and left the facility before the first practice began.

This doesn't include quarterback Joe Flacco missing the first week of camp with a back injury. The Ravens are hoping this isn't a lingering issue.

Ravens offensive lineman John Urschel announced his retirement before the start of training camp Thursday morning. Rich Graessle/Icon Sportswire

While this has been an unusual amount of bad luck, the cumulative loss should be put in perspective. The only player who was penciled in as a starter was Pitta. Young would've played a lot of snaps as the third cornerback, Dixon would've shared snaps with Terrance West, and Urschel might have been able to beat out Ryan Jensen and Matt Skura at starting center.

What also shouldn't be overlooked is the return of key players. Two Pro Bowl starters -- guard Marshal Yanda (shoulder) and linebacker C.J. Mosley (shoulder) -- were on the field to start camp after missing all of the offseason practices. Tight end Benjamin Watson was also catching passes in his first full practice since tearing his Achilles.

This is not the ideal start for a team that has missed the playoffs in three of the past four seasons since winning the Super Bowl. Losing players has been a troublesome trend for Baltimore. Over the last two seasons -- in which the Ravens have gone a combined 13-19 -- the team has placed 37 players on injured reserve.

The Ravens moved forward on Thursday with their first practice, with their focus on the Sept. 10 opener at the Cincinnati Bengals and hopefully a change in fortune.

"The show must go on," nose tackle Brandon Williams said.