However, manager Terry Francona and pitching coach John Farrell both said that health is not an issue for Beckett, who has a 9.82 ERA in his past three starts while giving up 10 home runs.
"It wasn't vintage Beckett, but that doesn't mean we need to set off the alarm bells or anything like that," said Francona. "He's not hurt. He's not throwing 79 mph. He's had a couple of outings that aren't up to his standards."
The issue, as it usually is when Beckett struggles, is his command in the lower portion of the strike zone.
"Sometimes he can almost throw through that two-seam movement," said Francona. "It's hard because a guy like Beckett, you reach back and you want to throw it through the wall as opposed to letting some of the natural movement take over. That's why when he has that front-door two-seamer going against a left-hander, that's when he's at his absolute best. When we see that in the first inning, it's a great feeling because that almost gives him an extra couple of pitches."
Farrell is confident that all of the problems Beckett has had in his past three starts can be fixed in short order. On Friday night against the Blue Jays, Beckett walked five batters in a start for the first time since 2006. He also gave up five hits and five runs over five innings.
"There's been a lot of video breakdown; there's been a lot of discussion in between starts," said Farrell. "There's been a lot of specific focus on creating more of a consistent downhill plain to his fastball. I thought last night there were more pitches thrown to the bottom of the strike zone. Yet, what was a little bit uncharacteristic of Josh was get two quick outs and lose the strike zone for a couple of hitters, and then one curveball doesn't finish as it did earlier in the at-bat to [Aaron] Hill -- and it ended up costing him three runs.
"There are times still where he'll get a little bit spread out and not create the downhill leverage that he's been so good at for nearly three years."
Despite the recent lull, Beckett still has strong overall numbers (14-5, 3.80 ERA) for the season.
"The one thing he won't back away from is a challenge, whether it's preparation for his next start or accomplishing some of the goals he has," said Farrell. "The short-term goal is to regain that same type of consistency. This isn't a health-related issue. This isn't a fatigue-related issue. This is a little bit more of just some timing in his delivery to allow that execution at the bottom of the strike zone to be more consistent."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.