Blue Jays September Call-Ups: Which Players Are Options for Roster Expansion?

In September, major league rosters expand from 26 to 28. This is often when teams call up prospects to see what they can do at the top level. Due to injuries and poor performances, the Blue Jays have already had 13 prospects make their MLB debuts. They only trail the Chicago White Sox in the number of debuts they've seen this season. 

Brett Bateman, Kazuma Okamoto, Brandon Valenzuela, Charles McAdoo, Chad Dallas, and Spencer Miles are currently on the Blue Jays roster. Who could be the prospects to join these players in September?

Stats updated prior to games on August 27.

Hitting Prospects

Sean Keys

Sean Keys made his MLB debut on July 27. It was an unimpressive first impression; he slashed .167/.189/.278 with a home run, five runs, and five RBIs in 37 plate appearances. He struggled with chasing pitches at a 32.5 percent rate, which was unexpected given his 19.3 percent strikeout rate with Triple-A Buffalo this season.

Keys has also shown power in the minors, hitting 27 home runs over 421 plate appearances. With the lack of power on the Blue Jays, they hoped Keys would help. He posted an outstanding 60.9 hard-hit rate, but only a 4.3 barrel percentage in his brief MLB cameo. He didn’t show he was ready yet, so he was sent back down after less than a month with the big league club. He also wasn’t getting regular playing time, since Vladimir Guerrero Jr. and Okamoto blocked him at the corner infield positions.

However, being sent down has been good for the rookie. In 21 August games, he is hitting .370/.475/.679 with six home runs, 19 runs, and 22 RBIs. He’s proven that he deserves another shot at the big leagues this season. He’s still blocked at the corner infield positions, but he’s going to start playing left field with Buffalo. The Blue Jays like their versatile players, and Keys can be another weapon at several positions if he can succeed in the outfield.

Jay Harry

Jay Harry looked like a promising prospect in 2023, his first minor league season, with a .902 OPS. However, he struggled mightily over the next two seasons, posting a .679 and .572 OPS, respectively. He’s had a revelation this season and is flying up the minor league ladder. He posted a .934 OPS with Double-A New Hampshire, earning a promotion to Triple-A Buffalo on June 12, where he has kept the hitting going, with an .880 OPS over 161 plate appearances. 

The left-handed hitter doesn’t offer much power, with 13 home runs over 348 plate appearances between Single, Double, and Triple A this season. However, he’s getting on base with a .369 batting average on balls in play. The prospect has also reduced his 23.5 percent strikeout rate from Double A to 16.1 percent in Triple A. 

In addition, Harry should be more appealing for the major league team, having played every position except first base and catcher over his three minor league seasons. We all know how much Toronto loves utility players. Harry deserves a shot in the big leagues in September and has the advantage of playing multiple positions. The switch-hitting Brandon Valenzuela is the team's only bat off the bench who can hit left-handed, which would make both Keys and Harry smart additions to give John Schneider another lefty bat that’s not his backup catcher. 

Pitching Prospects

The revolving door the Blue Jays have had on their pitching staff this season leaves open the possibility that we may see quite a few different pitchers called up through September. There are 10 pitchers currently on their major league injured list; seven of them are starters. The number of starters unavailable has forced the Blue Jays to use a bullpen game for a rotation spot through a majority of the season. Those additional innings are why there have been so many call-ups, even if it's just for one game.

Ricky Tiedemann

It’s been a rough road for Ricky Tiedemann. He underwent Tommy John surgery in July 2024, forcing him to miss the following season. This season, he was briefly shut down in February with elbow discomfort and in early July due to neck discomfort. He finally made his long-awaited MLB debut on August 15, though it was brief. 

Tiedemann threw 1 2/3 innings, allowing one earned run on two hits and two strikeouts. He was sent down the next day, which may have just been a cautionary move to keep the injury-prone lefty’s workload down. Since returning to Buffalo, Tiedemann has thrown 3 1/3 scoreless innings, allowing two hits and striking out four, though he's walked two batters and hit one. 

His sweeper is his best out pitch. In a small sample of 27 pitches with the Blue Jays, he threw the sweeper 59.3 percent of the time, and it had a 33.3 percent put-away rate. Tiedemann may eventually be a starter, but that will come after stretching out during the offseason. He’s likely a lock to be called up at some point in September, even if it’s just for another cup of coffee.

Tanner Andrews

Tanner Andrews spent eight seasons in the minors (the 2020 minor league season was canceled). After a long waiting period, he finally received the special call on May 25. He pitched back-to-back days, totaling three innings and allowing one hit, but he walked two while only striking out one. Although he had a decent outing, he was designated for assignment on June 4. He cleared waivers and returned to Triple-A Buffalo, where he has a 2.05 ERA and a 1.47 WHIP over 44 innings.

However, he’s been better at striking batters out over his minor league career than the 9.1 percent rate he displayed during his cup of coffee with the Blue Jays. The righty had a 20 percent strikeout rate or higher in each of his minor league seasons, except his first season, in which he barely missed (19.7 percent).

Walking batters is a major issue for Andrews. He has a 15.3 percent rate at the Triple-A level this season, and it's been an issue over his minor league career. This is possibly the reason we haven't seen him back with the Blue Jays yet. The righty has been better in August, throwing 7 1/3 innings, allowing three earned runs off of six hits, walking four, and striking out seven. He's been used in high-leverage situations as well, earning two saves.

Andrews is a 30-year-old minor leaguer, so his time to contribute is running out. To give him another shot, he’d need to be added back to the 40-man roster. 

Daniel Guerra

Daniel Guerra is a long-shot prospect to make his MLB debut this season. It’s his fifth minor league season, but he’s flown up the ladder this season, making a stop at all four affiliate levels. He is one of the hottest pitching prospects in the Blue Jays’ farm system. He made 14 starts and three relief appearances between Single, High, and Double A before getting the promotion to Triple-A Buffalo on August 26. Even though the sample was small, Guerra was dominant in four Double-A innings, striking out nine of the 16 batters he faced.

The righty’s first Triple-A appearance wasn’t smooth, but it was a solid outing. He threw one inning, allowing a solo home run while walking one and striking out one. The homer was the only hit Guerra allowed. The phenomenal pitching and strikeout potential he possesses would be enough to deserve a call-up, but he’s had limited innings at the higher minor league levels. 

However, his move to the bullpen after moving to Double-A was meant to help him reach the big leagues quicker. The Blue Jays will be watching his next outing or two very closely. It’s not out of the question for Guerra to receive his phone call.