LHP Tugboat Wilkinson -- who throws an 'Invisiball' -- gets call from Giants (source)

CLEVELAND -- The Giants are planning to call up left-hander Matt Wilkinson from Triple-A Sacramento for their upcoming series against the Guardians this week, a source confirmed to MLB.com on Monday. The club has not confirmed the news.

Fellow southpaw Carson Whisenhunt is slated to pitch Tuesday’s series opener, but the Giants have yet to name a starter for Wednesday. Wilkinson, who is nicknamed “Tugboat,” last pitched for Sacramento last Thursday, so he could be an option to slide into the rotation that day, or pitch behind veteran right-hander Adrian Houser.

Wilkinson, 23, was acquired from the Guardians in exchange for catcher Patrick Bailey in May and could have a chance to make his Major League debut against his former organization, creating an interesting subplot for the Interleague clash at Progressive Field.

Wilkinson is known for his “Invisiball” fastball, which averaged just 89.9 mph and topped out at 92.2 mph at Sacramento. While Wilkinson doesn’t light up the radar gun, he creates deception with his low release point, allowing him to hold Triple-A hitters to a .172 average with his four-seam fastball this season.

Wilkinson threw his fastball 61.9% of the time with Sacramento, though he also mixed in a slider, changeup and cutter.

Wilkinson was dubbed "Tugboat" by his dad's best friend, Phil McNeil, when he represented Team Canada in the Little League World Series. Wilkinson's own explanation: "I wasn't moving too fast around the bases growing up."

• The best nicknames in Minor League Baseball

Subsequently, Wilkinson was a contender in the "Knickname Knockout" competition earlier this season, in which fans voted on which Minor League player had the best nickname. He ultimately finished third; Peyton Williams won for his moniker of "The Iowa Meat Truck."

Wilkinson isn’t on the 40-man roster, so the Giants will have to clear a spot for him before officially selecting his contract. The 6-foot-1, 250-pound hurler would have been eligible for the Rule 5 Draft if he weren’t added to the 40-man roster this offseason, which likely factored into the Giants’ decision to give him a late-season look in the Majors.

A 10th-round Draft pick of the Guardians in 2023, Wilkinson is 6-6 with a 3.40 ERA and 96 strikeouts over 90 innings across four Minor League levels this year.

Wilkinson was dominant this season at Double-A, going 3-2 with a 1.87 ERA between Akron and Richmond. He’s endured some struggles since his promotion to Triple-A, though, going 3-4 with a 5.15 ERA in 10 starts.