By Michael Hurley, CBS Boston

BOSTON (CBS) — It’s been a very strange first half of the season for the defending-champion Boston Red Sox. The ace of their staff represents arguably the strangest development.

After allowing five runs over six innings of work, Chris Sale left the game against the White Sox on Wednesday afternoon at Fenway Park with the Red Sox trailing 5-3. In doing so, Sale guaranteed that he would not be picking up a win on this day — something that’s been the story of his season when pitching at home.

Wednesday was Sale’s eighth start of the season at home, and he entered the day with an 0-2 record and 3.79 ERA at Fenway. After his work on Wednesday, the ERA rose to 4.27, with the record remaining at 0-2, thanks to an eighth-inning rally to give Boston a late lead. And with the Red Sox heading to London before a trip to Toronto and Detroit, the home record will remain at 0-2 through the All-Star break.

The Red Sox would eventually lose Wednesday’s matinee, courtesy of Matt Barnes serving up a two-run homer to Jose Abreu in the ninth, dropping the Red Sox to 2-6 in games started by Sale at Fenway this year.

Combined with last year’s semi-shutdown, Sale hasn’t won a game at home since July 11 of 2018. That means that Sale will go a full calendar year without picking up a regular-season win at Fenway Park. (He did pick up the win against the Yankees in Game 1 of the ALDS.)

Sale also allowed his sixth home run of the year at Fenway on Wednesday. He allowed just three home runs at Fenway all season last year, in 12 starts.

The reasons for Sale’s struggles at home have been somewhat difficult to pinpoint. He’s still striking out opponents at a high rate. His 10 strikeouts Wednesday gave him his sixth 10-strikeout performance at Fenway this year, but only one of those games led to a win for Sale.

His control has suffered a bit, but not to an extreme degree. He’s walked 1.75 batters per start at home this year, compared to 1.42 batter per start a year ago. So the walks have not come with that much more frequency, but Sale’s nevertheless struggled to last deep into games.

In his eight home starts, Sale has finished off the seventh inning just three times. He’s yet to record an out in the eighth inning. He’s averaged 5.2 innings per start. He needed 102 pitches to get through six innings on Wednesday, after requiring 101 pitches to get through five innings in his last home start.

Of course, Sale’s year on the whole in 2019 has been a struggle. Last year at this time, he was 7-4 with a 2.56 ERA. This year, he’s 3-7 with a 3.82 ERA.

Sale has had trouble coming up with an explanation for the step backward, especially once he regained his normal fastball velocity.

And as is the case whenever looking at wins and losses for starting pitchers, the end result of the games have not always been his doing. Likewise, the Red Sox as a team have had their issues at home, as they are now just 20-20 when playing in the friendly confines of Fenway Park.

Nevertheless, with the Red Sox still struggling to climb into a real race in the AL East, the lack of home victories for the ace of the staff has certainly been a rather significant story line through the first half of the season.