After his horrific two-inning, seven-run outing Monday night in the Red Sox' 16-5 loss to the Rays, Daisuke Matsuzaka now has pitched 100 regular-season games in a Red Sox uniform. 

Mystery unsolved.

That's right. As hard as it might be to fathom, we aren't any closer to figuring out what exactly this team has in this pitcher as we were when Matsuzaka arrived just more than four years ago.

He walked off the mound Monday night with a 46-29 career mark and a boatload of boos. Not exactly the scene many envisioned when trying to define the pitcher four years ago.

Let's start at the beginning ...

The first pitches Matsuzaka threw to batters as a member of the Red Sox was on Field No. 2 at the team's minor league training facility. The hitters were guys named Bobby Scales, Kevin Cash, Luis Jiminez and Jacoby Ellsbury, with Jason Varitek as the catcher.

"Impressive," Ellsbury said after the 44-pitch batting practice session. "His fastball got going as he went along. But his breaking balls were really tight, which is what you want."

We didn't know what to make of him.

A few days later Matsuzaka pitched in a real, live game, facing Boston College in the Red Sox' 2007 spring training opener. In front of a park full of curiosity, the 26-year-old rookie threw 25 pitches -- 15 fastballs, five sliders, three curveballs and one splitter -- all of which drew the extra attention from those in attendance.

"He's a little guy, huh?" said one National League talent evaluator upon first glance of the mystery man.

Judging by the legend that followed Matsuzaka, we figured he must stand 10 feet tall with a 150 mph fastball ready to burst from his right arm.

We still didn't know what to make of him.

In Matsuzaka's first real game, a start in Kansas City, he allowed just one run in seven innings, striking out 10 and walking one. He hit 95 mph on the gun, while getting Royals outfielder David DeJesus to say, "I saw lot of different stuff when I was up there. I don’t know what to call them."

It would be one of the better games Matsuzaka has thrown. He never eclipsed the 10 strikeouts, reaching that total just two more times in his Red Sox career -- once 12 days later and again on Aug. 4 of that same season.

We thought we knew what to make of him, but that wasn't entirely the case.

Ninety-nine regular-season starts later and here we find Matsuzaka, having just turned one of the three worst outings of his Boston tenure. Just two other times has the righty left the mound in two innings or less.

But when it comes to Matsuzaka it never has been as simple as zeroing in on the hits and runs in one, isolated outing in cementing an opinion regarding the pitcher. Reason? There has been just enough good to keep the confusion (or illusion) alive.

Twenty-nine times Matsuzaka has lasted seven innings or more, going 20-3 with a 1.54 ERA when going that distance, holding hitters to a .188 batting average. And, in case you forgot, five of the 12 times he has managed to go as many as eight innings came as recently as last season.

Then there is his ability to dig out from the kind of depths he finds himself in after Monday night. Following what was perhaps the worst outing of his career (a one-inning, seven-run horror show against the Cardinals on June 21, 2008), Matsuzaka went on one of the best runs of his career -- five games, 30 2/3 innings, three runs.

But, as we sit here, history won't help Matsuzaka. 

There is a reason the Fenway Park crowd has little hesitation when it comes to sending verbal disapproval the way of Matsuzaka. Despite being together for five seasons, collecting a batch of postseason memories along the way, the fans and the pitcher are far from connected.

At first it was just befuddling not knowing what to expect from Matsuzaka, but now, from the public's perspective, it has been simply annoying. 

One hundred starts. No answers.

It's not what anybody signed up for.