Taijuan Walker's return to Seattle may have come about three months late, but the long wait appears to finally be over.
A right-handed fireballer listed as the fifth-best prospect in baseball by MLB.com, Walker is set to make his season debut against the Astros on Monday in Minute Maid Park. The talented 21-year-old was expected to begin the season in the Mariners' starting rotation, but shoulder inflammation kept him sidelined for nearly all of Spring Training. A setback during one of his April rehab starts would further delay the arrival date.
"He's done everything we've asked him to do, he's healthy and it just makes sense for him to come back," Mariners manager Lloyd McClendon said.
No longer dealing with shoulder pain, Walker will begin the second stint of his Major League career after going 1-0 with a 3.60 ERA in three starts last September. He went 2-1 with a 4.11 ERA in six starts with Triple-A Tacoma this season, including a complete-game shutout in his last start that featured more strikeouts (eight) than hits (four).
Walker primarily relies on his four-seam fastball, which regularly sits in the 95-97 mph range, while also mixing in a cutter, curveball, splitter and sinker.
"His starts have been fine," McClendon said. "The one before [the shutout], he had some ups and downs, but all pitchers do. From a health standpoint, he's feeling better, he's throwing, he's answering the bell every five days. The velocity is up and he's building, so that's encouraging."
The Astros are certainly no stranger to Walker, having faced him twice last season during his September callup. He held the club's lineup to three runs (two earned) over 10 innings, striking out 10, scattering seven hits and walking two.
Houston will counter with right-hander Collin McHugh (4-6, 2.86), who finds himself in the midst of a breakout 2014 campaign.
Over his last five outings, McHugh has turned in a solid 2.96 ERA to go with a pair of quality starts despite issuing 15 walks over that span. He made his Astros debut against the Mariners back in April, limiting them to three hits over a scoreless 6 2/3 frames while registering a season-high 12 strikeouts.
"I think Collin is a great example of a guy who keeps working hard and putting us in a position to win ballgames," manager Bo Porter said. "We stand behind all our guys on the mound, and he's given us no reason not to be confident when he's out there."
The Astros and Mariners have split the season series thus far at five games apiece, tying a four-game set in Seattle last month and trading series wins before that. The two clubs will have met 38 times in their history entering Monday, with Houston holding a 20-18 overall advantage.
Astros: Keuchel progressing, aiming to make next start
Left-hander Dallas Keuchel wound up a late scratch ahead of Saturday's scheduled start due to inflammation in his left hand. However, the team is hopeful that's the only game he'll have to miss.
Keuchel had been wearing a soft cast over the weekend but was able to remove it and work in a throwing session before Sunday's series finale with the Tigers. The Astros consider him day to day.
"The swelling has gone down, and the training staff is good with how it's progressed, so if they're comfortable, I'm comfortable," Keuchel said.
Keuchel leads the club with 83 strikeouts to go along with a 2.78 ERA and eight wins in his third Major League season.
Mariners: Seager seeking All-Star recognition
Third baseman Kyle Seager may not find himself among the top All-Star vote-getters at his position, but his recent display at the plate may be changing his outside perception.
Through Sunday, the 26-year-old is hitting .277 with 20 doubles, 12 home runs and 55 RBIs on the season. He also leads all qualified American League third basemen in triples (three) while ranking second in batting average and slugging percentage (.490) to the Rangers' Adrian Beltre.
Seager has been especially productive of late, hitting .516 with four doubles over his last eight games.
• Astros outfielder Dexter Fowler missed a third straight game due to back tightness on Sunday. The team has listed him as day to day and expects the Fowler to avoid landing on the disabled list.
• Seattle reliever Joe Beimel entered Sunday riding a 15 2/3-inning scoreless streak, which is the longest active mark among American League relievers.
Alec Shirkey is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.