11:26pm: Gilbert told reporters (including Adam Jude of The Seattle Times) that he expects to go for an MRI tomorrow.

9:59pm: The Mariners announced that Logan Gilbert exited tonight’s start against the Marlins with forearm tightness. Gilbert had fired three perfect innings with a trio of strikeouts. He was lifted for Casey Lawrence to begin the fourth.

Gilbert’s fastball was in the 94-95 MPH range throughout the night. His final heater checked in at 95.4 MPH, right in line with his 95.6 MPH season average. The stuff still seemed sharp, but the M’s are obviously going to be extremely cautious with any kind of forearm discomfort. Gilbert entered play tonight with a 2.63 earned run average and 41 strikeouts through his first 27 1/3 innings. It was an even more impressive start than last year, when he landed sixth in AL Cy Young balloting after posting a 3.23 ERA over an MLB-high 208 2/3 frames.

Skipper Dan Wilson will presumably provide more information postgame. It’s impossible to know the severity this soon, but it’s a concerning development anytime a top pitcher experiences forearm discomfort. It wouldn’t be a surprise if the Mariners send Gilbert for imaging over the weekend.

Seattle opened the season without star righty George Kirby, who battled shoulder inflammation early in Spring Training. Kirby progressed to throwing a bullpen session before tonight’s game, his first mound work after a six-week shutdown (link via Daniel Kramer of MLB.com). He’s expected to throw live batting practice next week. Kirby appears to be progressing nicely, but he’s certainly still weeks away from a return to major league action.

Luis Castillo, Bryan Woo and Bryce Miller have filled their customary mid-rotation spots behind Gilbert. The final rotation spot has been a struggle in Kirby’s absence. Luis F. Castillo allowed seven runs in as many innings over two starts. Emerson Hancock has given up 10 runs across 11 2/3 frames in three outings.