Spring training is a bad time to evaluate players. Players aren't in midseason form, we don't know what they're working on on a given day, and the quality of competition can vary wildly from inning to inning, nevermind day to day.

And yet, dozens of players win Opening Day roster spots each year with their spring training performance, despite all that noise. One player forcing his way on to the Opening Day roster this year is Seattle Mariners first base prospect Dan Vogelbach, who went deep Friday and Saturday to give him four home runs in 51 Cactus League plate appearances. Here is Saturday's blast:

The 25-year-old Vogelbach comes into Sunday hitting .400/.529/.850 with more walks (10) than strikeouts (8) this spring, and he leads all players in extra-base hits (10) and is second to Jason Kipnis in total bases (34). He originally joined the Mariners two years ago, in the trade that sent Mike Montgomery to the Chicago Cubs.

Since the trade Vogelbach has played primarily in Triple-A, with a few big-league cups of coffee mixed in. Last season he hit .290/.388/.455 with 17 home runs in 125 Triple-A games, which is good, but not really great for a bad-only first base prospect. Consider the year before Vogelbach hit .292/.417/.505 with 23 homers in 133 Triple-A games. Repeating a level and taking a step back in performance usually isn't good news.

MLB: Spring Training-Seattle Mariners at Texas Rangers
Dan Vogelbach is hitting his way on to Seattle's Opening Day roster. USATSI

By no means is Vogelbach a top prospect. MLB.com ranks has the 11th best prospect in a thin Mariners system, and their scouting report acknowledges his "window to carve out a big-league role is fading." This was going to be a big spring for him no matter what. Going back to Triple-A for a third straight season would put Vogelbach in that dangerous Quad-A masher territory. That's not where anyone wants to be.

When Ryon Healy needed hand surgery early in camp, it created an opportunity for Vogelbach to get at-bats and jump into the MLB first base mix, which he's been able to do with his spring performance so far. Here's what Mariners GM Jerry Dipoto said about Vogelbach in the latest edition of his Wheelhouse Podcast, via MLB.com's Greg Johns:

"Vogelbach is making his case, whether Ryon Healy is ready or not, to be on our 25-man club," said Dipoto. "Whether that is sharing time at first base while Ryon's hand improves, whether it's a bat on the bench or in this case it might be helping Nelly out while Nelly recovers from his quad.

"But Vogey deserves to be on this club. He has raked from day one. He has controlled the strike zone really better than anybody in the Cactus League. What he's doing with the bat is reminiscent of what he's kind of always done in the Minor Leagues, but we've never had the opportunity to see in the big leagues."

...

"Right now, Vogey is making it real simple to like what he's doing," Dipoto said. "He's been good and he's been good every day." 

Healy has since returned from his hand surgery -- he played his first spring training game Saturday -- though at this point, Vogelbach has already done enough to force his way into the lineup. The Mariners could platoon the right-handed hitting Healy and left-handed hitting Vogelbach, plus Vogelbach can get at-bats at DH as the club eases Nelson Cruz back into things following his quad injury. There are ways to get him into the lineup.

Who knows whether this will last. I mean, obviously Vogelbach won't keep up this pace, but can he repeat last year's Triple-A numbers in MLB? That's probably what he'll have to do to stick on the roster long-term. Life is tough for bat-only first basemen these days -- Adam Lind hit .303/.362/.513 with 14 homers in 301 plate appearances for a contender last year and he's still unemployed -- so Vogelbach will have to follow his big spring with a big regular season to stick around.

I know this much: Vogelbach wasn't going to make the Mariners with a poor spring training. He was going to have to mash to win a roster spot, and that's what he's done so far. Vogelbach has done the easy part. He's (probably) going to make the team. Now he has to perform well enough to stay in the big leagues, and that's the difficult part. For now, Vogelbach has opened eyes in spring training, and next he'll have a chance to show he's an MLB player after two years in Triple-A.