CLEVELAND -- If the past two weeks have proven anything, it¡¯s that the San Francisco Giants can be a dangerous team.

But, as of right now, they¡¯re not a complete team, either.

While the Giants¡¯ 8-5 showing over the last two weeks has helped move them back into the National League postseason picture, Sunday¡¯s 5-4 loss to the Guardians was a prime example of how threatening San Francisco¡¯s roster can be -- while also shining a spotlight on its deficiencies.

They got a solid start from Hayden Birdsong and another big hit from Michael Conforto (a Statcast-projected 440-foot two-run home run), but San Francisco's taxed bullpen ended up coughing up the lead when Sean Hjelle allowed a back-breaking, pinch-hit go-ahead three-run home run to Bo Naylor in the sixth inning.

"I made a [bad] pitch, and he put a good swing on it,¡± Hjelle said. ¡°That's it. Plain and simple. I need to make a better pitch in that situation."

An inning earlier, Hjelle saved the Giants' lead by striking out Jos¨¦ Ram¨ªrez with the tying and go-ahead runs on base. That changed in the sixth inning when he left a sinker over the plate that Naylor mashed to right field.

After the ball made contact with Naylor¡¯s bat, Hjelle briefly watched it fly towards the right-field bleachers before he put his hands on his hips and stared at the grass by Progressive Field¡¯s pitching mound.

Hjelle opened the sixth by retiring the first two batters, but the inning was extended when Andr¨¦s Gim¨¦nez reached base on a single that glanced off shortstop Nick Ahmed¡¯s glove. That was followed up by a fluky infield single from Tyler Freeman, which set up Naylor¡¯s heroics.

¡°I¡¯ll take my chances with Hjelle,¡± Giants manager Bob Melvin said. ¡°He [allowed] a bloop hit and then a ground ball. It happens sometimes.¡±

A day after former top prospect Kyle Harrison made his return from the injured list, Birdsong -- the team¡¯s No. 4 prospect -- allowed two runs in 4 2/3 innings.

¡°I felt really good at the beginning,¡± Birdsong said. ¡°I was making my pitches, and hitting my spots. I was hoping I¡¯d just keep doing that, but I fell behind a bit in the fourth.¡±

He only allowed one baserunner in the first three innings before the Guardians tagged him for two runs on four straight hits to start the fourth inning.

¡°Those guys are good hitters; that¡¯s a good team,¡± Birdsong said. ¡°Things happen, those guys can hit. I was happy I was able to work out of it, and we were able to keep the lead.¡±

The main reason he got out of the fourth inning was because of an incredible play from Matt Chapman to cut down the potential tying run at home.

The two-time Platinum Glove winner corralled a ground ball from Freeman and let loose a 73.4 mph seed to Patrick Bailey, who slapped a tag on Josh Naylor moments before he touched home plate.

The Guardians challenged the play to see if Bailey had blocked the plate, but the rule wasn¡¯t enforceable since it was a ball on the infield.

¡°You don¡¯t have time to position yourself; you just kind of go where the ball takes you when it¡¯s on the infield,¡± said Melvin, a former catcher himself.

Three pitches later, Birdsong picked Freeman off at first to end the inning.

While the Giants went 3-3 on the road trip, and have won three of their last four series, they¡¯re leaving Cleveland frustrated after dropping two straight games that they had opportunities to win.

¡°We were in every game on this trip,¡± Melvin said. ¡°I just would have liked to have been one game better.¡±

The Giants will take a big step toward looking like a more complete team on Tuesday when Blake Snell returns from a month-long stint on the injured list. While the reigning National League Cy Young winner hasn¡¯t pitched like an ace this year (9.51 ERA in 23 2/3 innings), his presence on the mound will be a boon for a Giants bullpen that¡¯s had to cover an MLB-high 141 1/3 innings since he was placed on the injured list on June 3.

Snell¡¯s start will kick off a six-game homestand that could end up determining the trajectory of the Giants' season.

¡°Our bullpen has continued to step up, and we¡¯re excited to get Blake back in there and some guys who can go deeper in games to take some pressure off our bullpen,¡± Melvin said.