After a stretch of 22 straight saves that earned Toronto Blue Jays' closer Roberto Osuna an All-Star nod and the title of one of baseball’s top young closers, the 22-year-old has struggled mightily in the second half of the season.

Including last night's blown save, which led to the Jays' 19-inning marathon loss against the Boston Red Sox, the righty now has an ERA of 6.00 in 24 innings pitched since the All-Star break and seven blown saves.
 

No panic or time to panic? Roberto Osuna's stats since the All-Star break

Saves/Save Opportunities 13/20*
ERA 6.00
Strikeouts 29 
WHIP  1.21

*Osuna leads the Majors in blown saves with 10

Some wonder if the young righty has been overworked, having already appeared in 61 games, racking up 59 innings pitched this season after logging 171 innings through his first two Major League seasons. Per MLB.com's baseballsavant, there's been a large dip in Osuna's four-seam fastball velocity from a year ago. In 2016, his four-seamer (FF) averaged 96.37 mph. It’s now down to 94.41 mph, possibly suggesting some arm fatigue.

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Average velocity by year for Roberto Osuna (via MLB.com)

However, there is reason for optimism.

According to Al Melchior​ of FanGraphs, Osuna's fastball velocity has improved in recent outings. On Sunday against the Baltimore Orioles, he averaged 95.1 mph and last night he averaged 94.9 mph – but both appearances resulted in blown saves.

FanGraphs notes that in his last nine innings, in which he has blown three of seven saves, he has only compiled a swinging strike rate of 10 per cent.

Melchior suggests that if Osuna can’t turn it around Blue Jays' manager John Gibbons could make a switch for the last few weeks of the season. Setup man Ryan Tepera or Dominic Leone could be candidates to take over in the ninth for the Jays.

Tepera has had a breakout season for the Jays, racking up a 7-1 record out of the pen with a 3.36 ERA and 73 strikeouts in 69.2 innings pitched. Meanwhile, Leone has had a very strong second half and become a mainstay after multiple call-ups from Triple-A Buffalo. The right-hander has posted a 2.19 ERA with 31 strikeouts and only five walks over 24.2 innings pitched since the All-Star break.