DETROIT -- The Red Sox are still trying to figure out what they have in Tyler Thornburg, who missed a season and a half with right shoulder troubles. And Thornburg is the first to admit that he's still trying to regain the form that made him one of the best setup men in the National League for the Brewers in 2016.
In a critical juncture on Saturday, Thornburg simply wasn't as effective as his team needed him to be.
"I feel like every outing, I feel like I'm right there," Thornburg said after Boston's 5-0 loss to Detroit at Comerica Park. "I feel like it's one thing away from clicking and getting on a roll. I don't know what that one little thing is yet, but I feel like that's why I kind of come out with a little bit of optimism every day.
"It's like, 'Is this going to be the day that something clicks?' I mean, honestly, I don't really care about the numbers right now. I want to get back to being the guy that I can be. I know, regardless of numbers, if I get back to that point at some period this year, then all of a sudden I'm going to be able to help a hell of a lot more than I am."
It had been a tight game up until Thornburg's entrance, with Boston trailing, 2-0, on the strength of a strong performance by Christopher Johnson. The lefty scattered five hits and two unearned runs over five innings, walking none and striking out five.
At a time when Eduardo Rodriguez, Steven Wright and Thomas Pomeranz (who returns Tuesday) are on the disabled list, Johnson has been strong as a rotation fill-in, posting a 2.24 ERA in five starts.
"BJ can pitch," Red Sox manager Alex Cora said. "He does a good job with what he has: going up in the zone, throwing the breaking ball, expanding down and in against righties. It looks like a comfortable at-bat, but it's actually not. We're very happy with the way he's throwing the ball. We're comfortable with him, and we'll keep rolling with him."
Detroit's two-run rally in the second was helped by Rafael Devers, who made his 20th error of the season in his first game back from the disabled list.
Jose Iglesias, who signed with Boston after he defected from Cuba and played for the 2013 World Series champion club, haunted his former team a couple of times on Saturday. The first was in that second, when he hammered one to left for a two-run double.
"I left it out over the plate," Johnson said. "I definitely wanted to get it in more."
But that was all Johnson allowed. With Johnson at 77 pitches through five, Cora called on Thornburg for the sixth. Johnson is still getting stretched out as a starter after spending most of the season in the bullpen.
"I think five innings right now is good for [Johnson]; 80 pitches. There was a high-leverage inning in the game, and we felt it was good enough for him," Cora said. "He gave us a chance. Hopefully, for the next one he goes six, but that was a good one."
Thornburg's night didn't start well, as John Hicks drew a leadoff walk. Victor Martinez followed with a single, putting runners at the corners with nobody out. Jeimer Candelario hit a sacrifice fly to left to make it 3-0. After Thornburg got the second out on a grounder, Iglesias turned on an inside fastball and ripped the 1-2 offering over the wall in left to break it open for Detroit.
"Fastball was good, breaking ball not so good," Cora said. "Out of the hand, it wasn't a competitive pitch. Also, the pitch to Iglesias was way in. For him to stay inside that ball and get to it, tip your hat to him."
Thornburg (10.38 ERA) has allowed at least one run in three of his first five appearances since his return from surgery to repair thoracic outlet syndrome in his right shoulder.
"There's a ton [to consider] after surgery, and reconditioning the arm to put up with the stresses of pitching and being ready to pitch. It's a lot, but hopefully something clicks sooner rather than later," Thornburg said.
Boston's dangerous offense has been mostly silenced in the first two games coming out of the All-Star break, scoring just one run over 18 innings. With a 69-31 mark, the Red Sox hold a 4 1/2-game cushion over the Yankees in the American League East.
"[We're] just getting back," star right fielder Mookie Betts said. "We'll be fine. Got to find some timing, a little rhythm. A couple of days off threw it off. Had some momentum going into the break, now it's just a matter of trying to create some more."
MOMENTS THAT MATTERED
Searching for offense all game, the Red Sox finally had a chance in the sixth when Devers and Eduardo Nunez struck for back-to-back, two-out singles. Up stepped Jackie Bradley Jr., and he hammered one to deep left. The hit seemed to have two-run double written all over it. But JaCoby Jones raced back and made a great catch, banging into the wall in left. Bradley's drive had an exit velocity of 103.9 mph and traveled 380 feet according to Statcast™. It also had a hit probability of 91 percent.

One inning later, it happened again. This time, Betts and Andrew Benintendi started the rally with one-out singles. Tigers manager Ron Gardenhire removed starter Mike Fiers and brought on former Red Sox righty Alex Wilson. Xander Bogaerts swung at an 0-1 curveball and hit a crisp grounder. Candelario, the third baseman, ranged over nicely to grab it, then made a crisp throw to second baseman Niko Goodrum, who fired to first for an inning-ending, 5-4-3 double play.

"The one Jackie hit, I thought that was way gone, but we're playing here, the wind was blowing in and it didn't happen," Cora said. "I thought the at-bats the second half of the game were a lot better. Hopefully tomorrow our timing is back and we win the series."
SOUND SMART
Betts continues to be an on-base machine, reaching at least once in each of his last 21 games, and batting .402 with 21 runs, six doubles, two triples, four homers and six walks during the streak.
YOU GOTTA SEE THIS
When Detroit's Leonys Martin struck one to deep right, he had the launch angle and the distance on the drive for a home run. But Betts ruined Martin's fun by drifting back to the wall, timing his leap perfectly and making a sensational grab. Betts went as high as he could go, reached his glove as far back as he could and reeled the ball in for the first out in the bottom of the third inning.

"He hit it high, and I wasn't sure if It was going to go or not. I was just able to time some steps and go up and catch it," Betts said.
HE SAID IT
"We're so lucky as a team to have that outfield, and it's just becoming a normal thing, as scary as that sounds." -- Johnson, on the catch by Betts and Boston's outfield defense
UP NEXT
Boston sends rested ace Chris Sale (10-4, 2.23 ERA) to the mound for Sunday's finale of this three-game series against the Tigers. Sale ended the first half on fire, going 5-1 with a 0.94 ERA over seven starts. Aside from the one inning he threw in the All-Star Game, Sale hasn't pitched since July 11. The Tigers will counter with lefty Blaine Hardy (3-2, 3.31). First pitch is set for 1:10 p.m. ET.