ST. PETERSBURG – Gage Jump will not be taking the mound again for the Athletics in 2026.
Three days after he exited his start against the Mariners at Sutter Health Park due to shoulder discomfort, Jump was diagnosed with a left shoulder impingement and placed on the 15-day injured list before Tuesday’s series opener against the Rays at Tropicana Field. The 23-year-old rookie left-hander will be shut down from throwing for the remainder of the season and focus on rebuilding his strength for a normal offseason throwing program.
Manager Mark Kotsay indicated that, had the A’s been in a playoff race, the club might have considered holding off on an IL decision for a few more days to see how Jump’s shoulder responds to treatment. Without much to play for other than valuable development time for the younger players on the roster, however, the decision became easy.
“We told him we were going to leave him back and make sure that this left shoulder impingement takes care of itself,” Kotsay said. “That’s where we’re at with just his level of strength and range of motion.”
Jump carried plenty of hype upon his arrival to the Majors. He was rated the A’s No. 3 prospect and No. 41 overall in baseball by MLB Pipeline at the time of his callup from Triple-A Las Vegas back in May. What they got from him in his first big league season was somewhat of a mixed bag.
Through his first seven starts, Jump posted a 2.93 ERA. The end of his season brought a ton of ups and downs, as he posted a 7.21 ERA over his final 13 starts. Overall, Jump turned in a 5.47 ERA in 20 Major League starts with 108 strikeouts and 46 walks across 98 2/3 innings.
“With Gage, a lot of expectations were on him when he got here,” Kotsay said. “That’s not easy to deal with. He’s a very talented young kid who went through a lot of ups and downs here at the Major League level for his first full year. There’s a lot to learn. There’s a lot to go forward with, which is exciting. We saw him at his best, and we saw him really grind through some starts. … Overall, he grew a lot and gained a lot from going through this experience this year.”
Even throughout those second-half struggles, though, Jump showed off the stuff that leads the A’s to believe he will emerge as a frontline starter. His electric fastball was consistently topping out around 98-99 mph, while his slider (37.4 percent swing-and-miss rate) and curveball (25.6 percent) proved to be strong secondary pitches that generated good swing-and-miss.
To take that next step, Kotsay and the A’s would like to see Jump continue to improve the usage and effectiveness of his changeup, a pitch he was hesitant to utilize early on in the season before getting more comfortable with it as the year went on. By the end of his season, it racked up the second-highest swing-and-miss rate (28.1 percent) of any of his six pitches.
“Gage is a hard worker,” Kotsay said. “Like most young players, he hadn’t fully understood everything it takes to have success here. One of the biggest things is being open-minded to change from a growth standpoint. There’s some stubbornness to Gage, and I think he’s understood that some of that stubbornness led to lack of results. But until you go through failure, that’s the only way you can learn.
“Those outings where it was difficult and challenging but there was still glimpses of success, most of those times were when he was getting swing and miss and punchouts. We’re fully aware he can get those [strikeouts]. The biggest adjustment he recognized was how successful he could be getting deep into games when he induces soft contact early in counts, utilizing that changeup, being able to land a breaking ball when behind [in the count] and getting ahead of hitters. Not chasing strikeouts. There was a lot that he learned and he’ll definitely be better for it.”
Jump’s absence creates an opening in the A’s rotation. Left-hander Joe Rock was recalled from Triple-A Las Vegas Tuesday as a corresponding move, though he’s expected to be utilized out of the bullpen, mostly for left-on-left matchups.
As for that next rotation turn, which would come Friday in Cleveland against the Guardians, Kotsay mentioned right-hander Mason Barnett as a candidate to come up from Triple-A to make that start. A bullpen game is also on the table.
“We’re going to wait until we get there on Friday,” Kotsay said. “We’ll see how we get there.”