Los Angeles Angels two-way sensation Shohei Ohtani is set to undergo season-ending surgery to address bipartite patella in his left knee, a rare congenital condition that was giving Ohtani discomfort as he increased the intensity of his bullpen sessions in recent weeks.
The surgery, which will be performed in Los Angeles on Friday, comes with an estimated recovery time of 10 to 12 weeks. The Angels hope Ohtani can get on the mound again in late November and conclude his 2019 throwing program the following month, at which point he will be shut down for the buildup to the 2020 season.
Angels general manager Billy Eppler said the team expects Ohtani to be ready to pitch at the start of spring training. Contributing as a designated hitter, which he will do on the days he does not start, is not a concern.
The Angels were considering delaying Ohtani's surgery until he completed his post-surgery throwing progression, but decided otherwise after consulting with Drs. Neal ElAttrache and Brian Schulz, who will perform the surgery.
"We felt like it was better to get it done now because it was causing some reluctance or apprehension, whatever word you want to use, in his mound progressions, and we wanted to continue to increase intensity," Eppler said on a conference call Thursday. "If we increased intensity and pushed on the intensity, and he compromised something in his delivery, that could lead to some unforeseen issues."
Bipartite patella is caused by the two bones of the kneecap not fusing together at birth, an issue present in no more than 2% of the population. Ohtani had been asymptomatic throughout his professional career, but it "aggravated him a number of times throughout the season," Eppler said.
Ohtani, who underwent Tommy John surgery shortly after the 2018 regular season, had been off a mound since late June and was throwing his fastball up into the mid-80s. The 25-year-old spent this season primarily as a designated hitter, finishing with a .286/.343/.505 slash line with 18 home runs in 425 plate appearances.
The bipartite patella did not necessarily affect Ohtani offensively -- Eppler referenced similar sprint speeds and exit velocities from his 2018 season -- but did impact the amount of weight he took on during squatting sessions.
The Angels presented the possibility of surgery on Tuesday morning, and Ohtani made the decision 24 hours later, prior to homering in what would be his final game of 2019. Ohtani is expected to activate his arm again in two to three weeks, at which point he will slowly increase the intensity once again. The Angels are hopeful that Ohtani can return to the mound at about the 10-week mark.
"He will hopefully conclude his throwing program at some point in early December," Eppler said, "at which point we'll give him appropriate time off and derive our program at that time for what that looks like going into 2020."