BOX SCORE

CHICAGO — The first-place Cubs opened a three-game series against the Seattle Mariners in a game that was the backdrop for a franchise icon’s return.

Sammy Sosa made his way back to Wrigley Field on a Friday when the Cubs’ bullpen had a rare bad day in a 9-4 loss. Chicago (45-30) fell to 11-2 in home series openers with the defeat.

Here are three takeaways from the loss to Seattle (38-36):

Sammy’s home

The talk of Friday was the return of the former Cubs slugger, who made his first trip back to the Friendly Confines since 2004.

Sosa met with Cubs chairman Tom Ricketts upon his arrival, toured the clubhouse and met players, including star outfielder Pete Crow-Armstrong.

“He’s doing fantastic,” Sosa said in a media availability during the game. “He’s swinging the ball very well.”

The slugger was honored during the daily “Legends of the Game” segment at Wrigley Field, and received a rousing ovation from the 40,787 fans in attendance. Sosa joined the radio and television broadcasts before speaking to local media.

Sosa was the talk of the day. Cubs manager Craig Counsell fielded pregame questions related to Sosa for about seven minutes, before briefly providing injury updates on Shota Imanaga and Porter Hodge (they’re pitching for Iowa on Friday), Miguel Amaya (he’s begun throwing and hitting in Arizona) and Javier Assad (he’s still throwing bullpens in Arizona).

[WATCH: Sammy Sosa joins Cubs Postgame Live!]

It’s rare that this strong Cubs team takes a back seat for anyone this season. Sosa made Friday an exception.

Bullpen’s rare off-outing

The Cubs’ bullpen had been so good for long that it felt due for an inevitable bad day.

It happened Friday — and to two of their hotter arms.

Ryan Pressly – who had 16 consecutive scoreless appearances before Friday – allowed a two-run homer to Mitch Garver in the sixth inning. The veteran had hit a low point on May 6, allowing nine runs (eight earned) in a tough extra-innings loss to the San Francisco Giants. Since then, however, he had thrown 15 scoreless innings, allowing only one unearned run with three walks and 14 strikeouts.

Pressly’s command had improved, and he begun to touch 95 mph with his four-seam fastball again. On Friday, though, he allowed a walk and the homer, spoiling his scoreless run and allowing Seattle to tie the score.

Left-hander Caleb Thielbar had been on an even better run – and it was snapped by an AL MVP candidate in catcher Cal Raleigh. Thielbar had gone 17 consecutive outings without allowing a run, and that streak was broken by Raleigh’s two-run blast — his second of the game and 29th of the season.

Thielbar had started the season slow – he allowed four runs in his first seven outings (5.2 innings) for a 6.35 ERA — but he locked it down and developed into a key member of Counsell’s reliever corps.

It was unrealistic to expect both Pressly, Thielbar or even left-hander Drew Pomeranz (who has yet to allow an earned run in his first 21 outings) or right-hander Chris Flexen to never give up an earned run again. The nature of relief pitchers means they’ll give up some runs — and they’ll hurt — but it’s more about how they will bounce back from this outing.

Boyd’s fast hands

Matthew Boyd had his shortest outing at Wrigley as a Cub, as the left-hander pitched just five innings of two-run ball, but he still had a memorable moment.

Mariners shortstop J.P. Crawford hit a 104.7-mph liner back to Boyd on the final pitch of his outing, and the pitcher caught the ball for the final out — on a play more instinctual than skill-based.

It came at a price, however, as Boyd was forced out of the game with a shoulder bruise.

Boyd allowed two hits and two walks with six strikeouts on 76 pitches. He’s been so crucial for the Cubs this season, with a 2.84 ERA this season in 85.2 innings across 15 starts.

The Cubs’ rotation has dealt with injuries to their co-aces — Shota Imanaga and Justin Steele — but been buoyed by Boyd and Jameson Taillon’s performances in their absence.