CLEARWATER, Fla. -- Jake Arrieta on Thursday offered an unexpected explanation for his second-half struggles in 2018: he pitched much of last season with an injured left knee.
The Phillies said Wednesday that Arrieta had minor surgery last month to repair a torn meniscus in his left knee following an incident during a weight-training session in Texas. Arrieta said that he felt pops in the knee during the workout, but also said he sustained the original tear in June, maybe earlier. Phillies manager Gabe Kapler said the team did not know until recently that Arrieta had been battling a knee issue last year.
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"I was able to pitch pretty effectively and it didn't bother me too much in between starts," Arrieta said. "Then in the offseason training, just doing some routine stuff, moving around a little bit, I came up out of the seated position and there were a couple pops. It didn't feel right."
Arrieta said he will be ready to open the season in the Phillies' rotation.
"Pretty much now on the same page as everyone else in camp," he said. "Really no setbacks. I have thrown three or four bullpens. Another one lined up for tomorrow, with no restrictions. The timing actually was really nice that it happened when it did. If it would have happened now or two weeks ago, I might have had a setback of some sort. We're in a good position."

The Phillies said they have no concerns about Arrieta's knee.
"Zero," Phillies general manager Matt Klentak said.
"Jake's a tough individual, so he's not the kind of guy who's going to let on that something's bugging him, because there's a lot of pride there," Kapler said. "My understanding was that it was an injury that he sustained during one of his workouts. … Obviously, Jake knows his body very well and he was feeling it last season."
Arrieta was 5-6 with a 3.54 ERA in 15 starts through June. He was 5-5 with a 4.36 ERA in 16 starts the rest of the way, although he had a 6.35 ERA in his final nine starts.
"It was something I was dealing with," Arrieta said. "I made it work the best I could. I was a little ginger getting out of the box sometimes, and getting over to first was a little bit of an issue. It wasn't enough to keep me off the mound. I was hoping it was something I could avoid. But obviously it wasn't."
If a healthier Arrieta pitches more like he did in the first half last season, it bodes well for the Phillies' rotation -- all the more, if they end up signing Bryce Harper or Manny Machado in the coming weeks. Arrieta shares an agent with Harper. He played with Machado in Baltimore.
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Like teammate Rhys Hoskins, Arrieta thinks the Phillies will sign one of the two superstars.
"I'm pretty optimistic about it," Arrieta said. "Really. I think there's probably a handful of teams still in the running. There's no inclination that we're not the favorite, or at least one of the favorites. I don't think it's going to come down to the money. I think it's going to come down to the players deciding what city, what team is the best fit for them. Where do they fit in the best? It's tough to say. But I could definitely see at least one of those guys here."
The rotation
Speculation continues that free-agent left-hander Dallas Keuchel could land in Philadelphia. The Phillies failed in their attempts to sign left-handed starters Patrick Corbin and J.A. Happ in the offseason, so the connection makes sense. Philadelphia maintained last offseason that they would not sign Arrieta, but then his price dropped, and the Phillies signed him on March 12.
"I would never rule that out as a possibility, just because we are opportunistic and we're always going to explore that," Klentak said about adding a starting pitcher. "But I still feel really good about our pitching depth at the Major League level, our pitching depth throughout the Minor Leagues, and we've got a lot of guys who are waiting in the wings in Triple-A that are looking forward to an opportunity. I feel very good about our depth if one of our top five guys can't post for whatever reason."